Finally get to pretend I am one of the cool kids - Holley kit swap

[72bluNblu]

I understand. I like the idea that I don't have to weld a seam all along the floor, but in the end a one piece tunnel welded all the way around probably is less welding in the end. Time will tell.

I don't think the 8HP tunnel is anywhere close to the size of one that fits a T56 in my case either. The T56 seems to be much taller just looking at how far up into the firewall my cuts are compared to yours.

If I were to do a one piece tunnel, I would consider a tunnel out of a late model Mopar like @Cool Hand did here.

But I wouldn't want it to go so far back. And it would be buckets only.

And no idea where I would even source the tunnel.

You won't have to take the tunnel modifications back as far as they did with that late model tunnel, but they do have to go back pretty far. Mine goes pretty much all the way back to the front of the floor reinforcement for the rearmost bucket seat mounts. The removable panel behind my shifter is open in the center so the shifter (not the handle) can be in place when the transmission is installed or removed. I did that so that I could install/remove the transmission by itself without having to angle it down like 1° at a time while I was sliding it back out of the bell. Otherwise the shifter stub would hit the tunnel. The way mine is set up it can come pretty much straight back until the input shaft is almost entirely out of the bell before you have to start dropping it down. If anything, if I were to do it again I would probably take that opening back another couple inches.

I run the A-body console in mine, it sits further back than the factory location to line the shifter up with the console. Doesn't leave a ton of space for the Procar seats, but there is some.

 

[Dantra]

You won't have to take the tunnel modifications back as far as they did with that late model tunnel, but they do have to go back pretty far. Mine goes pretty much all the way back to the front of the floor reinforcement for the rearmost bucket seat mounts. The removable panel behind my shifter is open in the center so the shifter (not the handle) can be in place when the transmission is installed or removed. I did that so that I could install/remove the transmission by itself without having to angle it down like 1° at a time while I was sliding it back out of the bell. Otherwise the shifter stub would hit the tunnel. The way mine is set up it can come pretty much straight back until the input shaft is almost entirely out of the bell before you have to start dropping it down. If anything, if I were to do it again I would probably take that opening back another couple inches.

View attachment 1716347559

View attachment 1716347560

I run the A-body console in mine, it sits further back than the factory location to line the shifter up with the console. Doesn't leave a ton of space for the Procar seats, but there is some.
View attachment 1716347561

I like the shape!

 

[Ozyduster]

Did i read that you have to cut the fire wall? With the hollley mounts you shouldn't have to cut the firewall at all sue to engine moving forward?

 

[DionR]

Did i read that you have to cut the fire wall? With the hollley mounts you shouldn't have to cut the firewall at all sue to engine moving forward?

Yes, I had to cut forward of the pinch weld. I lost some time trying to figure out why since I assumed that with the motor forward I wouldn’t have to cut as much. But I think Holley didn’t just move the motor forward, they moved it up about 3/4” as well.

Also, I have the big cast aluminum bell which doesn’t help any. The QuickTime bell is shorter at the top of the trans and might make a decent difference.

I have enough room for my factory heater box, but not sure about a factory AC box. I documented some of the things earlier that setting the motor up did. Not saying they were absolutely necessary, but the stuff Holley built around that motor location would make it tough to lower it.

I have in the back of my mind that if I like the Hemi enough, I could see swapping the motor into my ‘74 with the A833OD using the Holley stuff and doing more of an edgier build and using different mounts and headers to set the motor back and down for better weight. But that is just an idea and for now I am ok with the compromises.

 

[340sFastback]

I cut my firewall pinch weld out of trans tunnel and butt welded custom tunnel to that. Nice and smooth looks a lot better that way to get rid of pinch weld all together.

 

[DionR]

I cut my firewall pinch weld out of trans tunnel and butt welded custom tunnel to that. Nice and smooth looks a lot better that way to get rid of pinch weld all together.

In the end, most of my pinch weld will get removed as well.

 

[340sFastback]

In the end, most of my pinch weld will get removed as well.

I first bent mine over, struggled to get huge cast aluminum bell housing to fit, then my wife yelled at me and said go buy the Quick Time. I said ok if you say so. Then sold cast bell housing to someone on here who wanted it.

 

[DionR]

I first bent mine over, struggled to get huge cast aluminum bell housing to fit, then my wife yelled at me and said go buy the Quick Time. I said ok if you say so. Then sold cast bell housing to someone on here who wanted it.

I have your swap bookmarked and remember when you were struggling with getting your AC box to fit since the cast aluminum bell was taller.

 

[racerjoe]

Yes, I had to cut forward of the pinch weld. I lost some time trying to figure out why since I assumed that with the motor forward I wouldn’t have to cut as much. But I think Holley didn’t just move the motor forward, they moved it up about 3/4” as well.

Also, I have the big cast aluminum bell which doesn’t help any. The QuickTime bell is shorter at the top of the trans and might make a decent difference.

I have enough room for my factory heater box, but not sure about a factory AC box. I documented some of the things earlier that setting the motor up did. Not saying they were absolutely necessary, but the stuff Holley built around that motor location would make it tough to lower it.

I have in the back of my mind that if I like the Hemi enough, I could see swapping the motor into my ‘74 with the A833OD using the Holley stuff and doing more of an edgier build and using different mounts and headers to set the motor back and down for better weight. But that is just an idea and for now I am ok with the compromises.

It just occurred to me that they may have raised the engine for alternator clearance at the front frame rail pinch weld when using the car front cover.

 

[DionR]

It just occurred to me that they may have raised the engine for alternator clearance at the front frame rail pinch weld when using the car front cover.

Could be. I haven't tried an alternator on the motor yet to see.

I was guessing they did it to fit a bigger oil pan. The stock A-Body pan is like 3 or 4 quarts, this one is 6 quarts and hangs below the k-frame about 1/2" even with the motor sitting up.

 

[Dantra]

I have enough room for my factory heater box, but not sure about a factory AC box.

if I like the Hemi enough...

I ditched the oem AC box for aftermarket.. for a few reasons. The factory box is just an space hog and it looked like there was just going to be too many clearance issues.I could barely get it back in, just after increasing my tunnel size just a little was one. Also, if I had gone much bigger, the floor duct would have been a big deal. Another reason is, I just didn't see enough room for the dbw pedal. I was ready to upgrade anyway. I just felt like I was constant battle to get cold air. It would be fine.. then it wouldn't. But space was was the biggest factor, since all of my electronics are housed in the dash. I played around with the USCT pedal bracket over the weekend. I'll post in my thread here in a bit. You'll see that the pedal needs that room that the ac box wants as well..

"if I like the hemi enough"... @racerjoe , would you like to chime in here LOL. I think all of us have sold all of our small block parts and will never look back.

 

[340sFastback]

I had to pull padding off the back of carpet and it barely fit between floor heat duct and raised tunnel. Had to wressle it into place. I rebuilt my factory heat AC box, Sanden compressor, parallel flow condenser, and got 48 degree air in 95 degree plus weather. Could feel tips of ears getting cold. But that factory heat AC box is a big heavy pig. Since mine a factory AC factory 340 car trying to minimize the hacking modifications where possible. Because its a sin to do anything with a factory 340 car other then 100 percent stock right?

 

[Dantra]

I had to pull padding off the back of carpet and it barely fit between floor heat duct and raised tunnel. Had to wressle it into place. I rebuilt my factory heat AC box, Sanden compressor, parallel flow condenser, and got 48 degree air in 95 degree plus weather. Could feel tips of ears getting cold. But that factory heat AC box is a big heavy pig. Since mine a factory AC factory 340 car trying to minimize the hacking modifications where possible. Because its a sin to do anything with a factory 340 car other then 100 percent stock right?

What pedal are you running.

I had previously rebuilt the entire AC system and ran a sanden compressor with the old small block. It seemed ok but it was later in the year and not alot of hot temps left. Well then I did the Hemi swap that winter, used the Hemi compressor, upgraded the condenser etc. but it just never was as cold as would like all the time. I tried several things but was just never totally happy with it. In town driving was it's weak point. In hindsight, I think oil was my biggest issue.. That and so many other heat producing things around the condenser. But having to pull it all back out after doing the tunnel work was it for me.. done! I am not wrestling that thing ever again haha. Plus, I just need the room. I almost didn't get it out.

Consider me a sinner.. 340 car or not, I'd make it the way I wanted

 

[racerjoe]

I ditched the oem AC box for aftermarket.. for a few reasons. The factory box is just an space hog and it looked like there was just going to be too many clearance issues.I could barely get it back in, just after increasing my tunnel size just a little was one. Also, if I had gone much bigger, the floor duct would have been a big deal. Another reason is, I just didn't see enough room for the dbw pedal. I was ready to upgrade anyway. I just felt like I was constant battle to get cold air. It would be fine.. then it wouldn't. But space was was the biggest factor, since all of my electronics are housed in the dash. I played around with the USCT pedal bracket over the weekend. I'll post in my thread here in a bit. You'll see that the pedal needs that room that the ac box wants as well..

"if I like the hemi enough"... @racerjoe , would you like to chime in here LOL. I think all of us have sold all of our small block parts and will never look back.

Phht, if you don't like a G3 hemi swapped A-body, you're just weird!

 

[DionR]

I ditched the oem AC box for aftermarket.. for a few reasons. The factory box is just an space hog and it looked like there was just going to be too many clearance issues.I could barely get it back in, just after increasing my tunnel size just a little was one. Also, if I had gone much bigger, the floor duct would have been a big deal. Another reason is, I just didn't see enough room for the dbw pedal. I was ready to upgrade anyway. I just felt like I was constant battle to get cold air. It would be fine.. then it wouldn't. But space was was the biggest factor, since all of my electronics are housed in the dash.

I wonder how much the later AC box would change that. The earlier box is a 2 piece deal while the later ('73+ ??) is a one piece integrated unit.

Either way, AC is definitely in the cards for me, but it's a long way off. When I do get there, I have an idea in the back of my mind to use a Ram box much like @BadAss71 did here, minus the big firewall cut (I hope).

Worst case, I will go aftermarket.

Either way, I want the stock heat only box to fit for when the car first rolls down the road.

 

[DionR]

"if I like the hemi enough"... @racerjoe , would you like to chime in here LOL. I think all of us have sold all of our small block parts and will never look back.

Phht, if you don't like a G3 hemi swapped A-body, you're just weird!

I should have said that differently. Let me better explain.

The motor I am working with in the car is a core I am using as a mockup. The "good" motor (that is also a core) is on a stand and will get pulled down for a hone and rings assuming the rust in the bore doesn't require an overbore. Either way, I expect to have an extra motor laying around which has had me do some daydreaming about what I might do with it.

With a moderate build with just a 6.4 cam/intake and shorty headers, I could see the second motor being built up and a little spicier. Bottom level would be better heads and a bigger cam, upper level might be a forged shortblock, dual drilled heads and a HC FEAD so I could put a HC supercharger on it built in stages. Or maybe it sits in the corner and I buy a 6.4.

This daydreaming has me thinking about the overall build and the idea that potentially if I go a little bigger on the motor, I could see "rebuilding" it using different mounts and such to remove some of the compromises like the motor being forward and up and not having long tubes. So there is the additional potential that the Holley mounts and headers could end up in the same pile as the mild motor. This might mean no AC, or even bigger changes, but those questions get mulled over until much later.

Depending on how this build goes (thus the "if I like it" comment), I could see taking the first motor and the Holley parts and putting them in my '74 Duster 360. This is very much dependent on how much cutting is required and would not include the T56 and tunnel mods. The way the motor dropped in, I could see doing the swap and just adjusting some of the 4 speed parts like the mount, zee bar (or hydraulics) and building a shifter mount to maintain that location. But only if it is almost a bolt in. So my comment about "liking it" is less about the G3 and more about how well the swap goes in the end and if I want to jump through some of those hoops to put one in my '74.

Something to be clear about is that when the '73 hits the road with the G3/T56 I will have 2 running and driving A-Bodies with space to only really park one. The fact that one has the numbers matching LA and is a low production 4 speed car while the other is a go anywhere do anything more modern car means they can fulfill separate rolls for the most part. But if I swap a G3 into the '74 I would have 2 swapped cars and would really need to start thinking about getting rid of one. And it is on the periphery of my mind that once the '73 is on the road, I might not even want to keep the '74.

I have a lot of history with the '74 since I pulled it from the wrecking yard in '92. Makes it hard to think about parting with it.

 

[DionR]

I am so glad I didn't try and put the T56 in my '74. I originally bought the trans and the swap parts to do all of this to that car but when the '73 became available I transitioned the swap to the '73. After the cuts to the floor I wouldn't be surprised if I would have been so disheartened that the project would have stalled and died.

 

[Dantra]

I am so glad I didn't try and put the T56 in my '74. I originally bought the trans and the swap parts to do all of this to that car but when the '73 became available I transitioned the swap to the '73. After the cuts to the floor I wouldn't be surprised if I would have been so disheartened that the project would have stalled and died.

View attachment 1716349527

Nah, it wouldn't have died. Its just metal! I get more satisfaction out of making something my own, over keeping something "true". Build stuff the way want it and let the purists worry later..

So that's your floor now, in the 73? I like where it's going.

 

[DionR]

Nah, it wouldn't have died. Its just metal! I get more satisfaction out of making something my own, over keeping something "true". Build stuff the way want it and let the purists worry later..

It's not so much the idea that a purist might not like it. I have plenty of mods on the car already from 13" brakes to 17" wheels. It's more the idea that I can reverse the stuff I have changed with not much work. While the floor would be reversible, it would be at the expensive of a ton of work.

It's kind of like jumping off a cliff. Once you step off, you have to go all the way down before you can climb back to the top. And if you figure out half way down you are going to land on a rock, too bad.

Cutting the floor was like the first step off the cliff. No going back now, but with this car I'm not as worried about it.

So that's your floor now, in the 73? I like where it's going.

Yep, current condition. I thought I could leave some of the pinch weld for fixing later and the trans had other plans. And since I had to pull the bell to make some more cuts, I figured I might as well get some hex bolts to replace the allen bolts that came in my kit and are impossible to get a tool on with the firewall in the way. So I pushed pause and don't get to see the trans in place until I get the bolts.

 

[72bluNblu]

And since I had to pull the bell to make some more cuts, I figured I might as well get some hex bolts to replace the allen bolts that came in my kit and are impossible to get a tool on with the firewall in the way. So I pushed pause and don't get to see the trans in place until I get the bolts.

Yeah first thing I did was buy an ARP kit for all the transmission/bell housing bolts.

 

[340sFastback]

It's not so much the idea that a purist might not like it. I have plenty of mods on the car already from 13" brakes to 17" wheels. It's more the idea that I can reverse the stuff I have changed with not much work. While the floor would be reversible, it would be at the expensive of a ton of work.

It's kind of like jumping off a cliff. Once you step off, you have to go all the way down before you can climb back to the top. And if you figure out half way down you are going to land on a rock, too bad.

Cutting the floor was like the first step off the cliff. No going back now, but with this car I'm not as worried about it.



Yep, current condition. I thought I could leave some of the pinch weld for fixing later and the trans had other plans. And since I had to pull the bell to make some more cuts, I figured I might as well get some hex bolts to replace the allen bolts that came in my kit and are impossible to get a tool on with the firewall in the way. So I pushed pause and don't get to see the trans in place until I get the bolts.

Once you get it all together and you start banging gears with that T56 you'll be thinking best thing you ever did in your life.

 

[DionR]

Once you get it all together and you start banging gears with that T56 you'll be thinking best thing you ever did in your life.

I'm hoping it feels like my 2015 Challenger R/T 6M did, except lighter and faster, loved driving that thing. Setting the '73 up to have the same gearing and motor plus a little.