Modern Drivetrain Swap into '65 Valiant

[GGs66GT]

OK so you want and O/D first question is what rear axel ratio and tire diameter are you planning to run .
Once you figure that out you may not need O/D.

You may have a 2.94 or 3.23
Depending on tire diameter 24" 25" 26" 26.5" or 27" you nay not need O/D

I have P205 65R 15 in my Dart now with 2.94 gear and /6 904 , running around town I don't need 3rd its to tall . I will be changing to 3.23 gears and this should help. (see picture)

My only performance add is 2 1/4" exhaust from manifold to tail pipe with a muffler .
This made a big difference on the freeway lots of power . This was with P 225 60R 14 and 2.94

P 225 60R 14. 24.7" dia. 842 rev's per mile
P 205 65R 15. 25.4" dia. 817
P 245 60R 15. 26.5" dia. 781

 

[ScamperTom]

OK so you want and O/D first question is what rear axel ratio and tire diameter are you planning to run .
Once you figure that out you may not need O/D.

You may have a 2.94 or 3.23
Depending on tire diameter 24" 25" 26" 26.5" or 27" you nay not need O/D

I have P205 65R 15 in my Dart now with 2.94 gear and /6 904 , running around town I don't need 3rd its to tall . I will be changing to 3.23 gears and this should help. (see picture)

My only performance add is 2 1/4" exhaust from manifold to tail pipe with a muffler .
This made a big difference on the freeway lots of power . This was with P 225 60R 14 and 2.94

P 225 60R 14. 24.7" dia. 842 rev's per mile
P 205 65R 15. 25.4" dia. 817
P 245 60R 15. 26.5" dia. 781

View attachment 1715639445

Thanks for this! Sorry it’s been a little while since I’ve tried to wrap my head around this. What you point out about the gear ratio makes sense, but I’d rather have the options that the extra gear gives when driving around. My current dd has a 904 with a 3.55 rear, and i turn around 3000 rpm at 60 mph. Not ideal. It just doesn’t make sense to swap the motor and stay with 3 gears.

 

[AJ/FormS]

It just doesn’t make sense to swap the motor and stay with 3 gears.

back from the dead, but;
I put a 340 in a 65, back in the mid 70s, using a 65 A904 from a 273. It was a drop in. The only hiccups were the exhaust and the gas pedal. I installed some Hooker fenderwell headers, and a later cable pedal system, and that was that. Great swap. I would do it again. But with a torquey 360/or a Magnum, and a LU A999, and probably 2.94 gears or something.
With the V8 torque, in the lightweight Early-A, three gears is all you'll ever need. With 26.5 tall tires. 2.94s will get you ;
65= about 2400rpm in Lock-up, and
60= close to 4000 in Second gear, so you can leave the factory cam in whatever small block engine you happen to chose. This will be a lot of fun. And bonus, you can even leave the 2bbl on it, and even a lo-po exhaust system.You could even install 318 heads on a 360, I did it onto a 340, and it was still a gangbusters lil street combo.
If you are wondering how this can be;
Consider that the 225, if you had one, might make 180 ftlbs torque at 1800 stall. Thru the 904 and out the 3.23s in the back; this would be
180 x 2.45 x 3.23=1424 ftlbs into the rear axles.
But say you installed a 318Magnum with a 2400TC, and suppose it made 260ftlbs at 2400 , thru the 2.74 low gear ratio of the A999, and out the 2.94s in the back, that would be;
260 x 2.74 x 2.94 =2094 ftlbs into the rear axles.
That's nearly 700ftlbs/nearly 50% more torque, than with the slanty. As far as engine swaps go this is about as easy as it gets; you can do it in about a weekend; including a complete rear swap; (not just gears). If I had a long roof with a great body, this is what I would do. (well except I would install my 367HO into it, with the Hooker 5208 (IIRC) headers
I used to do this swap twice a year, in my 68 Barracuda DD; from a 360 4-speed with 3.55s, to a 318 A904 and a different rear chunk. Once in October, and back again in May; no big deal.
Whatever you decide;
Happy HotRodding.

 

[fig]

SRT4 motor will fit with plenty of room.

 

[ScamperTom]

back from the dead, but;
I put a 340 in a 65, back in the mid 70s, using a 65 A904 from a 273. It was a drop in. The only hiccups were the exhaust and the gas pedal. I installed some Hooker fenderwell headers, and a later cable pedal system, and that was that. Great swap. I would do it again. But with a torquey 360/or a Magnum, and a LU A999, and probably 2.94 gears or something.
With the V8 torque, in the lightweight Early-A, three gears is all you'll ever need. With 26.5 tall tires. 2.94s will get you ;
65= about 2400rpm in Lock-up, and
60= close to 4000 in Second gear, so you can leave the factory cam in whatever small block engine you happen to chose. This will be a lot of fun. And bonus, you can even leave the 2bbl on it, and even a lo-po exhaust system.You could even install 318 heads on a 360, I did it onto a 340, and it was still a gangbusters lil street combo.
If you are wondering how this can be;
Consider that the 225, if you had one, might make 180 ftlbs torque at 1800 stall. Thru the 904 and out the 3.23s in the back; this would be
180 x 2.45 x 3.23=1424 ftlbs into the rear axles.
But say you installed a 318Magnum with a 2400TC, and suppose it made 260ftlbs at 2400 , thru the 2.74 low gear ratio of the A999, and out the 2.94s in the back, that would be;
260 x 2.74 x 2.94 =2094 ftlbs into the rear axles.
That's nearly 700ftlbs/nearly 50% more torque, than with the slanty. As far as engine swaps go this is about as easy as it gets; you can do it in about a weekend; including a complete rear swap; (not just gears). If I had a long roof with a great body, this is what I would do. (well except I would install my 367HO into it, with the Hooker 5208 (IIRC) headers
I used to do this swap twice a year, in my 68 Barracuda DD; from a 360 4-speed with 3.55s, to a 318 A904 and a different rear chunk. Once in October, and back again in May; no big deal.
Whatever you decide;
Happy HotRodding.

That sounds like the perfect combo to make a fun and streetable car with classic parts! Don’t go overboard with the gears and hi stall converters, just keep it simple. I admire your commitment to swapping engines back and forth! I don’t think I’d have that kind of energy even tho it sounds pretty straightforward.

I’ve committed to swapping in a miata drivetrain, however, since the wagon is in worse shape than I was hoping and i have access to a bunch of cheap parts. The plan is to swap in the entire front subframe which will require new front frames. But the originals are pretty rusty so I don’t think that’s a problem. In fact half the car is gone at this point so a bigger challenge would be to put it back to stock.

SRT4 motor will fit with plenty of room.

View attachment 1715812443

View attachment 1715812444

Now that is what I’m talking about! What did you use for a transmission?

 

[BillGrissom]

SRT4 motor will fit with plenty of room.

Great and useful photos. It looks like the SRT engine was designed for the engine bay. I have the same 2.4L DOHC engine in my 1996 Voyager short-wheelbase minivan, but no turbo. A strange choice for a minivan. It has almost the same power as the 3.3L V-6 but you have to let the engine spin to get it. It surprises people when I floor it and it starts pulling hard >4000 rpm. Chrysler's earlier 2.5L 4 cyl was actually based on the slant-six, basically 2 cyl chopped off so they used the same tooling to machine the block. In my engine, the alternator would be up high on the driver's side, and the AC compressor down low on driver's side where it would likely interfere with the steering gear. The SRT components fit better. I doubt the aluminum intake manifold on my engine would fit as it wraps up higher than the valve cover, but Neons and PT's had a different plastic intake manifold that might fit.

Where did you attach the motor mount brackets, as my block has none there? Is the left one the mount for the power-steering pump? Was there a RWD version of the 2.4L SRT?

It is hard to find an SRT engine, though PT Cruisers used them and fell out of favor so now hitting junkyards. You'd have to check row52 regularly and grab an SRT when they first show. The VIN should tell if an SRT.

 

[pishta]

i think @slantsixdan debunked the slant heritage on the 2.0/2.x ohc fours but they are great motors. i has a 2.0 in a Breeze and i'd still be driving that wide car if the trans didnt start leaking and the paint didnt start peeling! But the V6 version in the Cirrus was the ticket: fast and torquey. That Mitsubishi 3.0 in the minivans and Diamantes was a great motor too. I had one in a Diamante but thr distributor was bad, kept dying on me. should have just fixed the bad harness but i traded it in on a Suburban! I prayed it had one more start in it to get it off the lot where i parked it.

 

[slantsixdan]

Chrysler's earlier 2.5L 4 cyl was actually based on the slant-six, basically 2 cyl chopped off so they used the same tooling to machine the block.

That (still) isn't even a little bit true.

It (still) won't be true tomorrow.

It (still) won't be true next week…or next month…or next year.

 

[GGs66GT]

The only thing the 2.5 had in common with the slant 6 is that it was mounted in a slanted position .

 

[jedrattle]

SRT4 motor will fit with plenty of room.

View attachment 1715812443

View attachment 1715812444

This peaks my interest. What trans options are there? I want a 6spd manual trans

 

[rapidtransitric]

Great and useful photos. It looks like the SRT engine was designed for the engine bay. I have the same 2.4L DOHC engine in my 1996 Voyager short-wheelbase minivan, but no turbo. A strange choice for a minivan. It has almost the same power as the 3.3L V-6 but you have to let the engine spin to get it. It surprises people when I floor it and it starts pulling hard >4000 rpm. Chrysler's earlier 2.5L 4 cyl was actually based on the slant-six, basically 2 cyl chopped off so they used the same tooling to machine the block. In my engine, the alternator would be up high on the driver's side, and the AC compressor down low on driver's side where it would likely interfere with the steering gear. The SRT components fit better. I doubt the aluminum intake manifold on my engine would fit as it wraps up higher than the valve cover, but Neons and PT's had a different plastic intake manifold that might fit.

Where did you attach the motor mount brackets, as my block has none there? Is the left one the mount for the power-steering pump? Was there a RWD version of the 2.4L SRT?

It is hard to find an SRT engine, though PT Cruisers used them and fell out of favor so now hitting junkyards. You'd have to check row52 regularly and grab an SRT when they first show. The VIN should tell if an SRT.

Great and useful photos. It looks like the SRT engine was designed for the engine bay. I have the same 2.4L DOHC engine in my 1996 Voyager short-wheelbase minivan, but no turbo. A strange choice for a minivan. It has almost the same power as the 3.3L V-6 but you have to let the engine spin to get it. It surprises people when I floor it and it starts pulling hard >4000 rpm. Chrysler's earlier 2.5L 4 cyl was actually based on the slant-six, basically 2 cyl chopped off so they used the same tooling to machine the block. In my engine, the alternator would be up high on the driver's side, and the AC compressor down low on driver's side where it would likely interfere with the steering gear. The SRT components fit better. I doubt the aluminum intake manifold on my engine would fit as it wraps up higher than the valve cover, but Neons and PT's had a different plastic intake manifold that might fit.

Where did you attach the motor mount brackets, as my block has none there? Is the left one the mount for the power-steering pump? Was there a RWD version of the 2.4L SRT?

It is hard to find an SRT engine, though PT Cruisers used them and fell out of favor so now hitting junkyards. You'd have to check row52 regularly and grab an SRT when they first show. The VIN should tell if an SRT.

Bill,
Jeep liberty was the rwd 2.4. I'm using a jeep liberty bellhousing with an ar5 5 speed from a pontiac Sostice. See post 167 of my build thread. "the wayback "

 

[fig]

A guy named Tony owns a fast Colt with a SRT4 motor. He made some adaptor plates to use a 904. I’m using a 727 with a gear vendor. He also provided the converter.

 

[fig]

Great and useful photos. It looks like the SRT engine was designed for the engine bay. I have the same 2.4L DOHC engine in my 1996 Voyager short-wheelbase minivan, but no turbo. A strange choice for a minivan. It has almost the same power as the 3.3L V-6 but you have to let the engine spin to get it. It surprises people when I floor it and it starts pulling hard >4000 rpm. Chrysler's earlier 2.5L 4 cyl was actually based on the slant-six, basically 2 cyl chopped off so they used the same tooling to machine the block. In my engine, the alternator would be up high on the driver's side, and the AC compressor down low on driver's side where it would likely interfere with the steering gear. The SRT components fit better. I doubt the aluminum intake manifold on my engine would fit as it wraps up higher than the valve cover, but Neons and PT's had a different plastic intake manifold that might fit.

Where did you attach the motor mount brackets, as my block has none there? Is the left one the mount for the power-steering pump? Was there a RWD version of the 2.4L SRT?

It is hard to find an SRT engine, though PT Cruisers used them and fell out of favor so now hitting junkyards. You'd have to check row52 regularly and grab an SRT when they first show. The VIN should tell if an SRT.

I apologize, I forgot about this thread. I’ll take som pictures tomorrow.

 

[BillGrissom]

That (still) isn't even a little bit true.

It (still) won't be true tomorrow.

It (still) won't be true next week…or next month…or next year.

Calm down. I have no dog in that fight. Just relating what I read somewhere, I recall a book about mod'ing Mopar engines, which might I might still have but don't care enough to look. That book discussed the 4 cyl engine since it helped me fix a smoking issue in our 1982 K-car (PCV plastic snorkel was installed upside down). In a quick google, this link says the 4 cyl was made in the same factory and had "some basic similarities", but was otherwise totally different:
"... 2.2 was introduced in 1981 as an all-new design, the first metric Chrysler engine. It was originally built at the Trenton Engine plant, which made the slant six and 440 RB. Though the two have some basic similarities, Pete Hagenbuch, who worked on both engines, wrote that "As far as I know there was absolutely no commonality between the 170/225 engines and the 2.2/2.5." The design philosophy may have held commonality, but not the actual design."
Chrysler (Mopar / Dodge / Plymouth) 2.2 and 2.5 Liter...

 

[slantsixdan]

Calm down

…said the man who decided to pick at a comment made in a calm tone without any exclamation-points or all-caps shouting…

…a month ago.

I'm not saying, I'm just saying, is all.

 

[BillGrissom]

…said the man who decided to pick at a comment made in a calm tone without any exclamation-points or all-caps shouting…

…a month ago.

No idea what you are fussing about this time. I said the OP's 2.4L SRT swap is clever. You are angry that somebody else published that the 2.0/2.2/2.5 L 4 cyl decended from the slant-six. I simply related that. Go find them to argue with (probably already did).

 

[slantsixdan]

No idea what you are fussing about

That makes…um…all of us, is my best guess.

You are angry

Bless your heart! I'm not, actually. Never was, on this subject or thread. I'm not sure what's driving you to keep kicking at this, but…have fun.

 

[harvenator]

In the spring I acquired a '65 Valiant wagon. The exterior shell seems to be in fine shape, but the floor is completely shot. The motor is locked up and I wouldn't trust the transmission either at this point. Since I'll have to complete major metal repairs as well as a complete driveline swap in any case, I would like to go with a good modern overdrive transmission.

The transmission is the focus here, as driveability is my priority with this car. I would like to keep a small motor in the car - no v8, although a 273 would be cool. It would be nice to keep the slant 6, but it doesn't seem like there are any straightforward overdrive options other than a 4-spd. Budget and simplicity are key. I was thinking about putting in a jeep 2.5 i4 or 4.0 i6 with an ax-5 out of a mid 90's Cherokee. Plenty of power for a small motor, and lots of support for the jeep guys. It would be nice to have a T-5, too. I could grab the engine and trans out of an S-10. Of course, maybe the work required to move away from the 904 isn't worth getting rid of the slant 6.

What do y'all think? What good motor/trans combo would be a good replacement for the factory setup?

Rebuild that /6. They're bullet proof as long as they're not over heated. There is also plenty of performance stuff for the slants available.

 

[ScamperTom]

After a long time in the yard I finally found time and space to push the valiant onto a lift for some major fab work.

Rust has really claimed this thing far more than I initially wanted to admit, so I thought it would be smart to install a basic six point cage to increase safety and structural rigidity, and provide a pickup point for the coilover mounts, which carry the full load of the suspension. Since this will be a street car, I didn’t build doorbars or interior supports, which would be a hazard for unharnessed passengers without helmets.

The old front subframe came out very easily. The sawzall cut through that old sheet metal so fast it shocked me.

Ready for new steel! I’ll post another update soon.

 

[AJ/FormS]

What do y'all think? What good motor/trans combo would be a good replacement for the factory setup?

With upsizing to a 318 comes more torque, that will allow you to run less rear gear with any old TF trans, but specifically the A999 will get you a low cruize rpm with reasonable take-off power.
Lemmee run this by you;
>Your wagon probably has 3.23s in the back and the A904 has a 2.45 low gear, giving you a starter gear of 7.91. with 27" tires this will cruise at about 2720 rpm.
With a .72 overdrive this might come down to 1960. A LU TC would knock it down to 1880. Your factory ignition system would NOT be able to supply the correct amount of advance for this rpm, so your fuel economy would suffer. And your throttle would be close to WOT to supply the needed power under those parameters.

>Lets see what a 318/A999 with 2.76s does.
Your starter gear would be 7.56= 2.76 x 2.74, but your 318 would be making way more torque, so the 318 will blast off quicker. In LU this combo will cruise at 65=2230, a much easier target to find adequate cruise timing for. The throttles will end up in a good place and 2230 is a pleasant cruise rpm.
NO overdrive required.
>This swap is so simple, that, if you had all the appropriate parts, tools, and knew your way around a tool box, you could do it in a weekend.

This is actually my dream bodystyle, but I would put a 360 into it lol. I had one in 75, and I have been kicking myself for decades, for giving it away.

EDIT:
OOps I see we are long past this,lol.

 

[Topless69]

Why couldn't a guy fab a custom pan and pickup, and "slant" a Jeep 6?

Or fab a power bulge on the hood?

 

[AJ/FormS]

I'm really starting to like the Second-generation Duster hoods. but the bulge is quite conservative. Maybe that's why I like it, lol.

 

[ScamperTom]

With upsizing to a 318 comes more torque, that will allow you to run less rear gear with any old TF trans, but specifically the A999 will get you a low cruize rpm with reasonable take-off power.
Lemmee run this by you;
>Your wagon probably has 3.23s in the back and the A904 has a 2.45 low gear, giving you a starter gear of 7.91. with 27" tires this will cruise at about 2720 rpm.
With a .72 overdrive this might come down to 1960. A LU TC would knock it down to 1880. Your factory ignition system would NOT be able to supply the correct amount of advance for this rpm, so your fuel economy would suffer. And your throttle would be close to WOT to supply the needed power under those parameters.

>Lets see what a 318/A999 with 2.76s does.
Your starter gear would be 7.56= 2.76 x 2.74, but your 318 would be making way more torque, so the 318 will blast off quicker. In LU this combo will cruise at 65=2230, a much easier target to find adequate cruise timing for. The throttles will end up in a good place and 2230 is a pleasant cruise rpm.
NO overdrive required.
>This swap is so simple, that, if you had all the appropriate parts, tools, and knew your way around a tool box, you could do it in a weekend.

This is actually my dream bodystyle, but I would put a 360 into it lol. I had one in 75, and I have been kicking myself for decades, for giving it away.

EDIT:
OOps I see we are long past this,lol.

We are long past that, haha, but I appreciate the breakdown nonetheless. I still have a lot to learn about how to make old combinations work, stuff that guys like you might take for granted.

If the chassis had been in better shape, I probably would have liked to keep the slant and figure out a good rear end option to make it work with a 4-speed overdrive.

 

[AJ/FormS]

I probably would have liked to keep the slant and figure out a good rear end option to make it work with a 4-speed overdrive.

I ran that box for three or more years behind my 367, and with three different cams, trying to like it. After breaking the third one, I got me a regular Commando and a GVod; problem solved. My complaint was that the gear ratios were just too far apart.

The thing is that the Convertor of any automatic transmission, is a Two-speed device, with an infinitely variable ratio between the two gears, and it's all automatic.
At zero mph, and at WOT, the TC will start in it's lowest ratio which is often at about 1.8
At top speed, still at WOT, the ratio may be down to 8% slip.
At cruising , the slip might be 3 or 4%
That makes your 3dpeed LU trans, act like a 4.5 speed.
Lets look at what I call road gears, which incorporates the rear gear and TC slippage.
Lets use the A999 and 2.94s
the trans ratios are; 2.74-1.54-1.00
Incorporating the 2.94s you get; 8.06-4.53-2.94
Adding the TC to first gear at 1.8@zero mph, you get; 14.51/8.06-4.53-2.94
Adding slip in each gear, say 15% at the top of first, 12% at the top of Second, 9% at the top of Third I get; 14.51/9.27-5.10-3.21 and 2.94 LU. I call LU a half gear; So this totals 4.5 ratios with the lowest automatically shifting. Lets stack that up with a TKO
The TKO is 2.87-1.89-1.28-1.00 and your choice of overdrives is .68/.72/.81
You need a starter gear of About 10/1 and a Final Drive of say 2.76. But the most important gear for a streeter is Second. So lets set the TKO up with a 5.10 ratio in third gear, to match the A999/2.94s. So then 5.10/1.28= 3.98s rounds to 3.91s in the back. Ok here we go, the road-ratios are
11.22-7.39-5.00-3.91-2.82 (.72od) Lets put the A999/2.94s under it; V
14.51-9.27-5.10-3.21-2.94LU as you can see,
the A999/2.94 is better in the first two ratios, same in third, and similar the rest of the way. It's really hard for me to love the TKO roughly $4000 bucks worth, when the A999 is already in my stable....
BUT, there is one fly in the ointment; that 14.51 ratio, as soon as the car starts moving OR if the tires spin, immediately starts to diminish towards it's 9.27 ratio. So, if your engine cannot sustain the torque input to the TC, it will fall on it's nose and perhaps even bog. Therefore Stall selection becomes important. Not to worry tho cuz you got a LU on the other end.
The other options are, a bigger engine with inherently more low-rpm torque, or more cylinder pressure to start with.
Finally; I have run that A999/2.94 combo, except no LU. but with a 2800TC; behind a lo-compression 318, and I liked it so much, that I tried it with 2.76s which I liked well enough to try again the following winter. With 2.76s this WOT combo was,
13.61-8.70-4.76-2.99- no LU compared to the;
11.22-7.39-5.00-3.91-2.82 (.72od) the TKO
Again, the Torqueflite wins where it counts, with top of second being 67mph @4000 which is about the powerpeak of the smoggerteen.
with 2.76s, 65=about 2300@3% slip

Almost everything I talk about, I have already tried.
If it seems like a lot, it's because I am coming 69 in June and have been messing with cars since 1969; which, at over 50 years, is a really really long time, lol.
For example;
If you need a narrowed 8.75 with Moser axles, 10 or 11" brakes, and say 4.88s, and a Trac-loc or a spool, I might be able to help you with that.lol.....

 

[ScamperTom]

I ran that box for three or more years behind my 367, and with three different cams, trying to like it. After breaking the third one, I got me a regular Commando and a GVod; problem solved. My complaint was that the gear ratios were just too far apart.

The thing is that the Convertor of any automatic transmission, is a Two-speed device, with an infinitely variable ratio between the two gears, and it's all automatic.
At zero mph, and at WOT, the TC will start in it's lowest ratio which is often at about 1.8
At top speed, still at WOT, the ratio may be down to 8% slip.
At cruising , the slip might be 3 or 4%
That makes your 3dpeed LU trans, act like a 4.5 speed.
Lets look at what I call road gears, which incorporates the rear gear and TC slippage.
Lets use the A999 and 2.94s
the trans ratios are; 2.74-1.54-1.00
Incorporating the 2.94s you get; 8.06-4.53-2.94
Adding the TC to first gear at 1.8@zero mph, you get; 14.51/8.06-4.53-2.94
Adding slip in each gear, say 15% at the top of first, 12% at the top of Second, 9% at the top of Third I get; 14.51/9.27-5.10-3.21 and 2.94 LU. I call LU a half gear; So this totals 4.5 ratios with the lowest automatically shifting. Lets stack that up with a TKO
The TKO is 2.87-1.89-1.28-1.00 and your choice of overdrives is .68/.72/.81
You need a starter gear of About 10/1 and a Final Drive of say 2.76. But the most important gear for a streeter is Second. So lets set the TKO up with a 5.10 ratio in third gear, to match the A999/2.94s. So then 5.10/1.28= 3.98s rounds to 3.91s in the back. Ok here we go, the road-ratios are
11.22-7.39-5.00-3.91-2.82 (.72od) Lets put the A999/2.94s under it; V
14.51-9.27-5.10-3.21-2.94LU as you can see,
the A999/2.94 is better in the first two ratios, same in third, and similar the rest of the way. It's really hard for me to love the TKO roughly $4000 bucks worth, when the A999 is already in my stable....
BUT, there is one fly in the ointment; that 14.51 ratio, as soon as the car starts moving OR if the tires spin, immediately starts to diminish towards it's 9.27 ratio. So, if your engine cannot sustain the torque input to the TC, it will fall on it's nose and perhaps even bog. Therefore Stall selection becomes important. Not to worry tho cuz you got a LU on the other end.
The other options are, a bigger engine with inherently more low-rpm torque, or more cylinder pressure to start with.
Finally; I have run that A999/2.94 combo, except no LU. but with a 2800TC; behind a lo-compression 318, and I liked it so much, that I tried it with 2.76s which I liked well enough to try again the following winter. With 2.76s this WOT combo was,
13.61-8.70-4.76-2.99- no LU compared to the;
11.22-7.39-5.00-3.91-2.82 (.72od) the TKO
Again, the Torqueflite wins where it counts, with top of second being 67mph @4000 which is about the powerpeak of the smoggerteen.
with 2.76s, 65=about 2300@3% slip

Almost everything I talk about, I have already tried.
If it seems like a lot, it's because I am coming 69 in June and have been messing with cars since 1969; which, at over 50 years, is a really really long time, lol.
For example;
If you need a narrowed 8.75 with Moser axles, 10 or 11" brakes, and say 4.88s, and a Trac-loc or a spool, I might be able to help you with that.lol.....

It does seem like you really have tried every combo! Do you work out the ratios ahead of time to figure out what you think will work or do you just break down combos you’ve already tried and like?

What you’re saying about the lock up 3 speed having in effect as many gears as the 5 spd manual (except in first where you lose the torque multiplication of the tc) makes sense. It shows why people like a well sorted auto as a road car. The problem is, if you haven’t already figured out what works like you have, and collected the parts, sometimes it doesn’t make sense to go down that road.

For instance, in my scamp i have a 318/904/stock tc. Which was an absolute dog with the 7 1/4 but made for a fine driving daily. After i spun in the rain because of the open rear i swapped to a ford 8.8 lsd with 3.55s. Which is safer imo, but only accentuates the cars lack of performance. The trans will shift (in drive) at or below 2500 rpm so now instead of having the perfectly split gearset you described i have a package that will not pull until it’s in third gear but revs at 3000 while cruising at 65! So the car only feels alive right from a stop or pulling past 60 mph. If i want a good crossover vehicle that performs well but will still drive economically daily, then switching to a tko does seem to make more sense than getting a different stall tc or a lockup trans.