Long-off 340 build

What kind of transmission setup would be best for street cruising?

  • 4-spd

    Votes: 10 38.5%
  • 4-spd w/ OD unit (like a GearVendors)

    Votes: 4 15.4%
  • Look for an applicable 5-spd

    Votes: 12 46.2%

  • Total voters
    26
-

knote72

Stupidity is not unilateral, we all pay the price
Joined
Aug 23, 2016
Messages
200
Reaction score
24
Location
Marcola, Oregon
I'm starting this topic now so I can keep a public list of plans I have for my build, and get feedback regarding them. I'm still in a position of working on my education and starting my career, but I figure now is a good time as any to start ironing out some of these ideas I have.

So for some time now the car I've wanted to get is a Dart Demon 340 (preferably the 71).
While the prospect of a badass muscle machine is a huge turn-on, what I'm really after is a fun street machine that'll be more than just a garage ornament (I don't just mean a weekend driver either). Even though I don't have much experience, I've done some research on the matter and I've got a small block to work on and get familiar with while I'm saving up (I also have a friend to help who knows his $h!t, he's a Chevy guy but he knows the engines of that era). So far I've put together a start list of ideas in mind for my build, as well as a starter shopping list:

*This list may change over time as I receive helpful input and/or go with different ideas

Any input on this one is appreciated. I still got plenty of time to look forward to, but I wanna try and snatch up my own Demon before they disappear (who knows what will happen, with the Challenger Demon getting attention they might suddenly get some increased popularity amongst collectors). In the meantime, I'll just open up my "Rebuilding small-block Mopars" book and get to know this lil 318 inside and out (once the pickup it's in wears out I may yank it out and save it for a future project)

220321-1000-0.jpg
 
Last edited:
Go get an automatic if cruising is your focus.
The cam dictates where your cruise rpm range will be and what gears it recommends as well to perform well...then you can figure the transmission or od you need...tire size will also impact. .......so what cam do you plan on running?
 
Go get an automatic if cruising is your focus.
The cam dictates where your cruise rpm range will be and what gears it recommends as well to perform well...then you can figure the transmission or od you need...tire size will also impact. .......so what cam do you plan on running?
Just because I wanna cruise doesn't mean I dunno how to drive a stick (emphasis on FUN street machine, just something that won't be too insane for regular driving)

I'm not sure exactly on the cam, that's the thing. Nothing with too crazy since I'd prefer to have enough vacuum to power brakes (although now that I think about it there are options for a canister or electric vacuum pump). If I use this thumper cam, I'll definitely have to use an alternate source of vacuum for the brakes > http://www.jegs.com/i/COMP-Cams/249/CL20-601-9/10002/-1?ymm=4294829732+4294829634+4294828937 Looks like a pretty high lift for trying to utilize any vacuum

I wasn't planning on straying on the ride height or tire size, so I figured I'd stick close to stock there (just not the stock Polyglas compound)
 
Last edited:
I'm starting this topic now so I can keep a public list of plans I have for my build, and get feedback regarding them. I'm still in a position of working on my education and starting my career, but I figure now is a good time as any to start ironing out some of these ideas I have.

So for some time now the car I've wanted to get is a Dart Demon 340 (preferably the 71).
While the prospect of a badass muscle machine is a huge turn-on, what I'm really after is a fun street machine that'll be more than just a garage ornament (I don't just mean a weekend driver either). Even though I don't have much experience, I've done some research on the matter and I've got a small block to work on and get familiar with while I'm saving up (I also have a friend to help who knows his $h!t, he's a Chevy guy but he knows the engines of that era). So far I've put together a start list of ideas in mind for my build, as well as a starter shopping list:

*This list may change over time as I receive helpful input and/or go with different ideas

Any input on this one is appreciated. I still got plenty of time to look forward to, but I wanna try and snatch up my own Demon before they disappear (who knows what will happen, with the Challenger Demon getting attention they might suddenly get some increased popularity amongst collectors). In the meantime, I'll just open up my "Rebuilding small-block Mopars" book and get to know this lil 318 inside and out (once the pickup it's in wears out I may yank it out and save it for a future project)

View attachment 1715053502
Very Impressive,.. You thought plans, before posting... Good stuff....
However, that Thumper grind , needs to be held in check... Until you know actual cylinder head flow, actual deck height(piston, above..., or below.. actual deck height(s...) I would ask what , you really wanna build ..(And think about it, deeply)...Make your money work for you,best... By researching ,here.....
 
If you have the funds I would go 5 speed so I voted 5 speed.

Just make sure all you parts... engine... trans... gears all work in the proper RPM range.
 
Since your using brand new high quality parts, you might as well talk to an expert about ordering a retrofit roller cam. then, you can also match up your torque converter also, if you intend on using an automatic. Combining these with experts in the field would be wise money spent.
 
Yeah the trans and cam are the only things I'm unsure of thus far. I considered a 5-spd but I didn't know of any particulars, I've heard of guys using 5-speeds from the 90s dakotas but I also heard those take some modding to fit and have a tendency to break (not like they're being bolted to big blocks or anything). I don't know of any other tranny that'll bolt on.

As far as cams go that thumper seems a bit wild and whacky for my goals (I was looking at roller cams for it and that's the mildest roller jegs had). I want something that will be a fun street machine, but not too much to the point where it only gets 9mpg and I can only afford to drive on the weekends. A light, sporty V8 that I can screw around with when I put the pedal down (not that I'll be breaking speed limits or anything, wink wink) but I can put on OD and be able to drive on the highway without revving out at 5000rpm and burning my mpgs (which is why I was questioning either a 4-spd w/ an OD unit or a 5-spd, cuz it's not like I'm putting big block torque to it).

As far as "expert" help, like I said I know someone who has a bit of history building cars, so he helped me get an idea where to start narrowing down my preferences. I also have my uncle with a bit of experience himself
 
shadydell, dwayne porter, strait line performance, etc. Smallblock experts.
I'll look at those first two, but straightline performance just turns up an atv shop. I took a 2nd look at 5-speeds for a bodies, and indeed some guys on here are adapting the trannys from the 90s dakotas

ax15 ?
NV3500 in my 74 Duster?

The NV3500 comes from the V8 94-04 dakotas, the year they had the 5.9L, so that'd be an option (although both look like they require some fab work to make fit).
 
The list you have and the thought process is very good.

The standard A-833 4spd is a very good trans. No weird gear drops.

The OD A-833 has slightly weird ratio spreads. A deep first gear and a tall final drive ratio due to the spread between 1st & 2nd & 3rd to 4th. 2nd to 3rd is a normal feel. You'll have a feeling like your winding out first to get to a good rpm for second and then again for 3rd to 4th.

The bell housing can be bought from Brewers. The retainer bearing is very large. And hard to find otherwise.

On 5spds. Tremac is a better plan though it is a bit more expensive than the other units listed which are probably at the junk yard and cheap.

(IMHO, go to a A-500 auto trans swap.)

On the other parts;

You can still get that MoPar dual plane? Wow!
My Hookers fit good on my Duster. A 2-1/2 system is an excellent t idea.

If you already have a V8 radiator, skip the aluminum radiator. Save money.

Rear end; If you have an 8-1/4, your good to go and go fast.

Brakes, factory discs set ups are good. No drums if your driving is "Spirted" or racing.

Vacuum pumps are used with big cams. But I guess it can't hurt. I see no real need for it as of yet.

You asked for a cam recommendation?
You'll get 50 different replies from 50 different people.

With a 3.55 gear & a unknown tire size given your goals, a nice and powerful street machine, I make this "General" suggestion;

Hyd. cam
Duration @ .050 of 230 - 236 on a 110 - 108 centerline with as much lift as you can get and the use of 1.6 rockers from Comp Cams or Hughesengines.

Add 4-6*'s for a solid cam.

You can start a cam search at Hughesengines.com
 
Last edited:
Just because I wanna cruise doesn't mean I dunno how to drive a stick (emphasis on FUN street machine, just something that won't be too insane for regular driving)

I'm not sure exactly on the cam, that's the thing. Nothing with too crazy since I'd prefer to have enough vacuum to power brakes (although now that I think about it there are options for a canister or electric vacuum pump). If I use this thumper cam, I'll definitely have to use an alternate source of vacuum for the brakes > http://www.jegs.com/i/COMP-Cams/249/CL20-601-9/10002/-1?ymm=4294829732+4294829634+4294828937 Looks like a pretty high lift for trying to utilize any vacuum

I wasn't planning on straying on the ride height or tire size, so I figured I'd stick close to stock there (just not the stock Polyglas compound)
Power brakes and cruising in od mean two things....limited power output and limited compression. The cam is gonna have to be small, hydraulic roller would be the fork that gets you the biggest bite of that best of both worlds.
Vacuum pumps are pricey, I have a friend that I built a .040 360 for, cam is lunati hyd roller 236@.050 .586 lift on a 110....the power brakes don't work too good after the first stop or 2 if consecutive...cruises nice with its lock up 727 and burns the tires....28 inch....
Where the he'll am I going with this?? Oh yeah, keep the @.050 at or under 230'ish and compression to about 9.5 so you don't under octane it at the pump, if you have 4 grand go but the passion 5 spd. Cruising is different for some of us, I cruise at 2800 n up because the damn things dirty under those rpms...but driving it like normal you couldn't tell until you start rolling around in 3rd or 4th at 2200 rpm and it starts bucking a tad or smells a Lil...but that's just the 251@.050 104* int solid roller I have in there..
 
Last edited:
Well said. I allready mentioned to keep the auto trans but just do an overdriven unit.
The manual trans allows for more cam. Hence my slightly greater duration @ .050 numbers.

I also went the route of a Hyd. roller in my wife's 360. It makes the most sense if you can swing the bucks. It has the greatest rpm range that is well suited for a mild build.

Her cam is a Comp & 224/230 @ .050 and should have 3.55's. The 3.23's will do for now. (26 inch tire)
 
Check with the manufacturer of the Fuel injection before you settle on a dual plane manifold. I think the throttle body injection systems prefer a single plane to run correctly.

As for the transmission I have the 833od and it is a little tricky to drive, fun but tricky. down shifting is almost impossible into second and impossible into first. someone had a GearVenders 833 on eBay a while back and it didn't sell for 3500. That sounds like I neat setup because it turns your trans into an 8 speed.
 
If you want good brakes without worries of a Vacuum signal, go hydroboost right out the gate. You will most likely end up with power steering based on what you have said so IMO you can be one and done with your brakes...

JW
 
If you want good brakes without worries of a Vacuum signal, go hydroboost right out the gate. You will most likely end up with power steering based on what you have said so IMO you can be one and done with your brakes...

JW
Hey JW, would you have a link as to "How to" install one of those?
It is a real good idea, run a cam as big as ya want, no worries.
 
Hey JW, would you have a link as to "How to" install one of those?
It is a real good idea, run a cam as big as ya want, no worries.

No, but let me put something together in a thread. Eazy peazy..... 2 people have driven my car other than me since putting it on the the road and one is a die hard Ford man. He was impressed and said the next car he has will have one. It eliminates the vaccum signal issue completely and you can go wild with the motor lol.....

JW
 
As far as price concerns here, let's assume the price factor is negligible

I didn't know there was an OD 833, I'd only heard of the 3-spd and 4-spd then the Passon conversion that fixes the 4-spd's awkward gear ratios. LS-300 mentioned Passon's 855 so I'm gonna see if I can dig up more on that

A couple of the parts I listed were just in case if the stock ones were pretty well gacked and worn. Who knows with the state of how a lot of these cars are kept. i.e. if the radiator is fine then I'll keep it. However I do plan on a full brake system swap, I know it's a lot of work but I've seen some hairy situations with old brake systems bringing up some "surprises". I'd just prefer to do a total brake system swap. Speaking of brakes, Slopar72 was talking about hydroboost. Is this what he meant? > Hydro-Boost Power Assist Systems: Operation Diagnosis and Repair Safe and accurate assumption on power steering, so I'd look forward to a thread on that

So the TBI prefers a single plane, according to you and other sources including Engine Masters https://www.youtube.com/watch?v=2sQJPZYSoUI the dual-plane seems to complicate proper delivery to all cylinders with the EFI for some reason. To be fair, their assessment of the EFI system was based on their own trial and error. If the EFI can match those numbers then I guess a single plane it is. Is it me or there more dual-plane intakes on jegs? Mostly dual-plane and crosswind, only found a dedicated single on summit > https://www.summitracing.com/parts/dcc-4529408/overview/

Assuming there's a viable solution in place for brakes, I can be more liberal (gotta be careful with that word these days) with the cam. For starters, what size were the polyglas tires on the Demon? I figure I'd stay close to that size. That tire size and 3.55:1 gear ratio on the 8.75" rear. The gear ratios on that Passon A-855 are: 1st - 2.64:1; 2nd - 1.92:1; 3rd - 1.40:1; 4th - 1.00:1; 5th - 0.70:1........they also say it withstands up to a constant 700ft-lb torque, but the 340 would be well within that range.
 
No, but let me put something together in a thread. Eazy peazy..... 2 people have driven my car other than me since putting it on the the road and one is a die hard Ford man. He was impressed and said the next car he has will have one. It eliminates the vaccum signal issue completely and you can go wild with the motor lol.....
Thanks, if you get it posted...
JW
Thanks.....
 
OH! There are also two different gear set for the A-833 besides the 3rd, OD trans.
Awkward ratios?
Yeah I heard that the ratios in the 4-spd 833 didn't match up quite right, like you had to drop to much rpm shifting into 2nd and so on
 
You want a Demon to cruise around in?

Get a V8, Flowmaster equipped automatic. You don't need a booster and you don't need four wheel discs. You're buying an old clunker that handles like crap, so drive according to the car limitations.

A word from a very happy Demon owner.....wind down the window and enjoy the mechanical soundtrack :).
 
I get the feeling my goal is being misunderstood a bit. I know I said "cruise", but what I want is a FUN, sporty STREET MACHINE that I can still drive around halfway normal (within reason, accessories like a/c not needed). Since "fun" for me is driving a stick, that more or less rules out the auto, which is okay. I daily drive a stick anyways. I just don't wanna be stuck maxed out at 60-65 on the highway (also why I'm leaning towards the 5-spd option).

Mr Gorsky's Flowmaster suggestion also gives me a starting point as far as exhaust system goes. I already figured headers of the 1.75" tube variety, and the rest of the exhaust system of the 2.5" variety (my state doesn't stress emissions testing or standards, but the fact that I'm leaning to the 71 Demon should cover me legally in the emissions dept).

Although, I don't feel the same towards brakes and handling expectations as Mr. Gorsky does. If I can make it a bit safer to drive I can, get the best of both worlds. The brake-update plan came in part from my friend the Chevy guy (for starters, shared a story of his brother's Nova rolling all the way through a red light because of old drum brakes). Considering that brakes are one of the main things that get restomodded on these cars, and preventing disaster for your "investment" only makes sense, brake conversion kits are readily available. Having an alternate option for powering brakes also frees up my option for a cam, which will still be up in the air for now.
 
Last edited:
Well OP you asked for opinions and you got em' lol.....

If I were you and young lol (guessing you are as such), here would be the attack mode.

Mild small block. Keep the weight off the front end and make it easier to do maintenance. Aluminum heads, shorty headers, and 90 octane able.

I like a GV but for what you are talking about doing definitely not. I am not familiar with ratios in later model tranny's but it would be no less than a 5 speed. Hack the car as necessary to make it work. As much as I cussed the McCleod Dual Disk in a previous build it was a soft pedal and good street manners and mechanical throwhout bearing.

I am also not up to speed as to how to make an A body handle modern but it will come at a price. For me it would be a stock rebuild with good shocks, sway bars, and steering box. I would be OK with using rubber components also.

Brakes would be a focal point. Disk aren't necessary in the rear but a match percentage front to rear with disk up front is. Add assist to that (as I said Hydroboost earlier) and you have good brakes.

Screw the A/C. I don't need it for this type of build though it's nice if you want to enjoy it on hot days. And definitely a clean sounding and installed stereo.

And lastly, take every thought of using a carburetor and let it go. Fuel injection full steam ahead with an Intank.

I had the most enjoyment with my Dusters with being able to just enjoy driving them. Anyhoo that is what I would be looking to do.

JW
 
-
Back
Top