Chevy L8P Crate engine & 6L80e Transmission in 71 Camaro

[Carlo C.]

Guys,
I am planning on installing the Chevy L8P (LT) crate engine and 6L80e trans combo in a 71 Camaro:

I have a lot of questions that I hope you guys can help me with.

I have been searching the internet trying to find out what needs to be done to make this 6L80 transmission work in this car. I have come to the conclusion that it does fit without cutting the tunnel, but it seems there is a problem with the pan hanging low under the car. I will have this car sitting a little low to look good. I seen people cutting and modifying the transmission pans, but most of the posts I was reading were rather old so I am wondering if anything has come out or if anyone has come up with a better solution?

I have figured out the shifter situation as shiftworks makes a shifter for the factory console for a 6L80/90 transmission so that was rather easy.

I had already bought a trans crossmember from Hooker Blackheart to install a 4L80 that I have for the car and was wondering if I can make that work with the 6L80 or do I need to get another one?

I was looking at the engine mount plates from Speed Engineering motor mount conversion plates, but was wondering if I can use the old school style solid motor mounts that are commonly used on the small block chevy stuff. I have the stock factory small block frame mounts on the car. This is what I would prefer if possible.



I was also wondering if the low profile LT oil pan from Speed Engineering would work on this engine?

I had links for everything but it would not allow me to post them yet. I am having problems even posting on this site. I tried all weekend from my laptop at home and could not post.


Thanks in advance for any help.
Carlo C.

[dhutton]

I am not aware of any low profile pans for the 6L80 transmission. I recommend you raise the tunnel. If you lower the car you will need to raise the transmission to get good driveline angles.

Don

[Carlo C.]

I am not aware of any low profile pans for the 6L80 transmission. I recommend you raise the tunnel. If you lower the car you will need to raise the transmission to get good driveline angles.

Don

Don,
I really don't want to raise the tunnel as I am a huge fan of the factory console and horseshoe style shifter and I think it would make it really tough to make all that work together. If I have too I will just stick with the 4L80 that I have. I did see a few posts on this site where guys where taking pans from a G8 and cutting them down.

Thanks
Carlo

[dhutton]

Don,
I really don't want to raise the tunnel as I am a huge fan of the factory console and horseshoe style shifter and I think it would make it really tough to make all that work together. If I have too I will just stick with the 4L80 that I have. I did see a few posts on this site where guys where taking pans from a G8 and cutting them down.

Thanks
Carlo

If you lower the car you will most likely have trouble with driveline angles if you don’t raise the transmission. If your driveline angles are bad you will have driveline vibrations.

It comes down to properly mocking everything up and verifying driveline angles at ride height.

Don

[sunandfun09]

Guys,
I am planning on installing the Chevy L8P (LT) crate engine and 6L80e trans combo in a 71 Camaro:

I have a lot of questions that I hope you guys can help me with.

I have been searching the internet trying to find out what needs to be done to make this 6L80 transmission work in this car. I have come to the conclusion that it does fit without cutting the tunnel, but it seems there is a problem with the pan hanging low under the car. I will have this car sitting a little low to look good. I seen people cutting and modifying the transmission pans, but most of the posts I was reading were rather old so I am wondering if anything has come out or if anyone has come up with a better solution?

I have figured out the shifter situation as shiftworks makes a shifter for the factory console for a 6L80/90 transmission so that was rather easy.

I had already bought a trans crossmember from Hooker Blackheart to install a 4L80 that I have for the car and was wondering if I can make that work with the 6L80 or do I need to get another one?

I was looking at the engine mount plates from Speed Engineering motor mount conversion plates, but was wondering if I can use the old school style solid motor mounts that are commonly used on the small block chevy stuff. I have the stock factory small block frame mounts on the car. This is what I would prefer if possible.

I was also wondering if the low profile LT oil pan from Speed Engineering would work on this engine?

I had links for everything but it would not allow me to post them yet. I am having problems even posting on this site. I tried all weekend from my laptop at home and could not post.


Thanks in advance for any help.
Carlo C.

The Pontiac G8 pan (6l80) is lower profile than the stock 6l80 pan. I am using that transmission/pan along with a Lokar dipstick in a Nova I'm building. You may have driveline angle issues depending on the trans cross member and will have to cut the tunnel anyway.

[Carlo C.]

The Pontiac G8 pan (6l80) is lower profile than the stock 6l80 pan. I am using that transmission/pan along with a Lokar dipstick in a Nova I'm building. You may have driveline angle issues depending on the trans cross member and will have to cut the tunnel anyway.

sunandfun09,
If there is no way of making this work without cutting the tunnel than I am just going to stick with the 4L80. It is a must for me to keep the factory console and shifter and not look all weird in the car. I already have the Hooker Blackheart/Holley crossmember for the 4L80. I had read some where on this forum that you could still use the Holley style mounts with just another plate on the engine.

Carlo C.

[72srcool]

Hey Carlo,

I just saw your post and I know it has been a while but if I can help I would like to. I put a L8T crate engine(the L8P wasn't out yet) in my 72 Camaro with a Tremec 5-speed. I put a Texas-Speed cam, springs and pushrods. I also did a CHE trunion upgrade and a LT2 Corvette intake turned around backwards with Speed Engineering mid length headers. I will tell you that this thing RIPS!! I used Speed Engineering LT mount plates to the SBC factory motor mounts. I cut the mounts down 1 inch to get the engine as low as possible to give me as much clearance in the tunnel for the transmission as possible.

Lance

[csouth]

Hey Carlo,

I just saw your post and I know it has been a while but if I can help I would like to. I put a L8T crate engine(the L8P wasn't out yet) in my 72 Camaro with a Tremec 5-speed. I put a Texas-Speed cam, springs and pushrods. I also did a CHE trunion upgrade and a LT2 Corvette intake turned around backwards with Speed Engineering mid length headers. I will tell you that this thing RIPS!! I used Speed Engineering LT mount plates to the SBC factory motor mounts. I cut the mounts down 1 inch to get the engine as low as possible to give me as much clearance in the tunnel for the transmission as possible.

Lance

6L80 is way bigger than a TKO/TKX... that trans is not going to work without cutting the tunnel. It won't even fit in an A Body without mods let alone and F Body...

[Carlo C.]

Guys,
Quick update. Car is almost finished and I decided to go with the 4L80 as it just made life a lot easier. It allowed me to keep the factory console and with the addition of a Shiftworks shifter kit for the 4L80 it looks great and has some cool new features. The Custom Built Transmission 4L80 is installed with a Circle D converter and I used the Holley Crossmember with 3" PST aluminum Driveshaft with Billet strange yoke to connect it to the 12 bolt rear. The car is currently at RCS motorsports in Fort Worth, TX getting wired. I normally do all my own wiring as it is something I enjoy, but I wanted this one over the edge nice and my work compared to Rick at RCS is like a all good high School football player compared to a Super Bowl winning all Pro. His work is just the best I have ever seen and I have been around a lot of nice cars that have been professionally wired. So I should have it back in another week and start putting all the final touches on it and getting ready for the HotRod power tour.

[cgoatz]

I’d love to chat with you about this swap as I am planning a L8p swap in my 1970 Chevelle.

[andrewb70]

I’d love to chat with you about this swap as I am planning a L8p swap in my 1970 Chevelle.

The L8P uses the same engine mounts as the LT1. For a GM A-body, I would look at the Holley LT swap pan and their engine mount kit.

Andrew

[Easytouring831]

What did it take to mate the 4l80 to the l8t? Are you doing a full manual 4l80? I can’t find any swap harnesses online for that combo.

[Carlo C.]

What did it take to mate the 4l80 to the l8t? Are you doing a full manual 4l80? I can’t find any swap harnesses online for that combo.

Easytouring831,

GM Performance doesn’t offer a standalone controller that will properly run a 4L80 behind this setup, so something had to give. Cutting up the floor to cram in a 6-speed wasn’t happening. I wasn’t about to lose the factory console just to row gears. Deal breaker.

So the GM ECU and harness hit the bench, and in went a Holley Terminator X (Gen V LT Direct Injection kit, 550-1631). If it was going to run, shift, and behave like it should, Holley was going to be in charge.

Of course, nothing worth doing is ever plug-and-play.

Holley doesn’t currently support the factory L8P DBW throttle body, which sent me down the rabbit hole until I got Nick Williams — the throttle body guru — on the phone. After walking through a few checks, he nailed it: ditch the L8P throttle body and run a 2019 Corvette unit. It’s physically identical to the L8P throttle body, likely with different internal electronics, but with one key difference — it actually works with the Holley system.

I would also highly recommend getting the pedal assembly from GM as well.

And here’s the important part: buy it from GM. Not the parts store. Not aftermarket. GM.

We tried a locally sourced replacement first. It failed immediately.

The genuine GM unit? Bolted on, synced up, and worked exactly like it should. No drama.

Here’s what fixed it:

Throttle Body – GM #12669871

DBW Pedal – C6 Corvette, GM #19417903

Holley DBW Pedal Bracket – #145-131 (drops right into the factory pedal location)

Once everything was mounted and calibrated, it flat-out worked. Clean throttle response, no glitches, no guessing.

Sometimes the right answer isn’t the easy one — but when it fires up and does exactly what it’s supposed to, you know you made the right call.

[Carlo C.]

Hey Carlo,

I just saw your post and I know it has been a while but if I can help I would like to. I put a L8T crate engine(the L8P wasn't out yet) in my 72 Camaro with a Tremec 5-speed. I put a Texas-Speed cam, springs and pushrods. I also did a CHE trunion upgrade and a LT2 Corvette intake turned around backwards with Speed Engineering mid length headers. I will tell you that this thing RIPS!! I used Speed Engineering LT mount plates to the SBC factory motor mounts. I cut the mounts down 1 inch to get the engine as low as possible to give me as much clearance in the tunnel for the transmission as possible.

Lance

Lance,

Sorry, I just saw your post. I’m running the full-length headers from Speed Engineering along with the Hooker Blackheart stainless exhaust. It did take a little modification to get everything to fit the way I wanted, but it turned out really well.

I took the car on the Hot Rod Power Tour and had an absolute blast. Since then, I’ve had it all over the place — even spent a full week cruising at Cruisin’ the Coast. I’m really enjoying putting miles on it.

Hot Rod did a photo shoot of the car, so now I’m just waiting to see when it finally hits print.