LSX Swap Questions [Archive]

Chevelle LT1

10-12-2009, 08:41 PM

Well, after denying my need for a faster ride long enough, I am getting set to replace the LT1 with something a bit newer (aka, LSX). At this point, I'm think that if I am going to that much effort, I may as well go ahead and swap the trans over from the 4L60E to a manual. I have been doing some looking, and the answer has been implied in others' posts, but never explicitly answered: If I am putting an LSX-T56 into my 70 Chevelle, will I have to do major tunnel surgery (beyond a BFH)? I would love to go the M/T route, but after only recently "finishing" the car, I really don't want to take that big of a step backwards. If anyone can provide any insight, it would be much appreciated.

~ Jason

rockytopper

10-13-2009, 05:01 AM

Yes your tunnel will require major reconstructive surgery with the t56. Many such builds on ls1 tech. The lower the car the more surgery required. Stock cars I beleive have been able to split the tunnel and weld in a strip in the middle while the cars that are slamed require a entire new tunnel.

130fe

10-13-2009, 05:39 AM

You might be able to do a TKO 600 swap and not hack your tunnel up. Just another option to think about.

68topls

10-13-2009, 09:23 AM

Looks like it will fit depending on what mounts you use. Read these two threads.......more of the first one.....

http://www.ls1tech.com/forums/conversions-hybrids/879985-1970-gto-version-2-0-a.html

http://www.ls1tech.com/forums/conversions-hybrids/1144698-mp-t70-1970-chevelle-pics.html

Chevelle LT1

10-13-2009, 11:33 AM

Thank you all for the references and suggestions. I will take a look at the links, and see if I can figure out a way to go. One question in the meantime: If tunnel changes are necessitated by getting the driveline angles correct, wouldn't it be possible to instead adjust the pinion angle and/or the motor mount pedestal height?

~ Jason

ProdigyCustoms

10-13-2009, 12:06 PM

You will cut your tunnel for either TKO600 or T56, but not a huge deal.

PhillipM

10-13-2009, 01:42 PM

So if you have to cut either way, I suggest going T56... I have driven both and believe me, the T56 is the way to go.

Andrew McBride

10-13-2009, 05:02 PM

You will cut your tunnel for either TKO600 or T56, but not a huge deal.

As much as I have read threads on this I never knew you had to cut your tunnel to fit a T56.

So according to what people have said, a 4l60e and a T56 will need to be modified to fit?

What about the 4l80e?

My car is already rhinolined and ready for install but if this is the case I am going to go back with a gen 1 block and 5 speed.

camcojb

10-13-2009, 06:00 PM

As much as I have read threads on this I never knew you had to cut your tunnel to fit a T56.

So according to what people have said, a 4l60e and a T56 will need to be modified to fit?

What about the 4l80e?

My car is already rhinolined and ready for install but if this is the case I am going to go back with a gen 1 block and 5 speed.
you won't have the tunnel problems with your Camaro, it's a Chevelle issue. It's funny since a Chevelle is bigger than a Camaro that it would have a smaller tunnel.

Jody

The WidowMaker

10-13-2009, 06:19 PM

both require surgery, and i cut out my entire tunnel front to back to make more room for the ds as well.

whats your rear gear?

Andrew McBride

10-13-2009, 06:21 PM

you won't have the tunnel problems with your Camaro, it's a Chevelle issue. It's funny since a Chevelle is bigger than a Camaro that it would have a smaller tunnel.

Jody

Thanks for the reply. Boy that makes me happy to hear that. I was bummed out thinking I was going to have to go back old school and I already have some of my LS1 parts! Sorry to get the thread side tracked.

Thanks, Andrew

Chevelle LT1

10-13-2009, 07:14 PM

Mike Holleman

10-14-2009, 09:44 AM

Glad to know that I'm not the only one this has been a surprise for. As to Chevelle tunnel surgery, have people found it better to split the tunnel in half and widen it with a filler piece, or to simply replace the tunnel altogether?
Having done several installs of this type, there is no right and wrong way. If you are buying your Tremec from an outfit like Keisler, they can provide a complete kit that will include directions and templates as to what you remove and what the replacement part will look like. I've done two of Keislers TKO500 installs in Chevys. One in a 55 and it required no tunnel mod except a hammer reshape. I did a 69 GTO and it required removing the upper part of the tunnel and adding a piece of sheet metal. They provided a template and it was an easy fit. I put a T56 in my Elky but it is a very different beast. I was working with new floor pans and the body is sitting on a Schwartz chassis that is solid mounted to the body and the engine is basically a solid mount. In other words I did not have to account for drivetrain movement. Highly recommend the folks at Keisler.
Mike