wrathfullprimate

I have a 68 camaro that had an automatic trans in it ... Well i never saw the driveline untill i picked up my LS1/4L60E. But it does have an automatic crossmember in it. Most likely for a TH350 or powerglide. Anyway using the motormount plates that i did (not sure what they are right now but a common one nonetheless) And the overdrive trans I moved the trans crossmember back about 3.5" and bolted it in. Do i need to try to keep any specific driveline pitch or do I only have to worry about tunnel clearance?
Here is an example of how the trans sits in between the frame and where the crossmember has ended up.
Comments please.

Rodder

iTrader: (2)

Are you sure that crossmember will fit there where the subframe is attached to the body? I don't think it will.

You want the angle of your driveline to match the angle of the pinion in the rear end, but in reality, a lot of people don't even bother to check it unless they are having a driveshaft vibration problem.

wrathfullprimate

Thanks for that, I havent tried it out yet. You are most likely correct but i think it still sits in the channel made to hold that crossmember. I will look closer at it this weekend. I made a crude highlight of where i think the recess is located, see if this pic looks better.


Ok this is something that someone else mentioned to me as well.

rsz288

The floor pan has recesses each side to allow the x member to sit higher and give additional exhaust clearance, so the x member in most cases, unless it is in the right place on the original 4 holes, will not just touch the floor pan, but interfere and probably prevent the subframe from bolting up right.

Cheers.

wrathfullprimate

@ rsz288: thanks for that info.. ill need to watch that when i check for clearance.

general update: I found my mounting plates and they are they type that locate an LS1 engine into a factory location in a car setup originally with a sbc so I am Figuring that if i got a transmission x-member it would be one that would convert a TH350 to a 4L60E using factory mount locations.

I might even build it myself if it comes down to it.

69LT1Bird

iTrader: (1)

The angle should be about 4* at each end.

I took the mounting pad on the crossmember and cut it off and welded it back on the other side. I have a 400 crossmember.

wrathfullprimate

OH does your crossmember have a mounting tab that was on the front side and you welded it onto the back side?

Mine is right in the middle.. here is a paint rendition from memory.

69LT1Bird

iTrader: (1)

Pretty much, you end up using only one hole in the old bracket. Its been in for about 7500+ miles now. Just check to make sure the trans pan stays close to level and the angles are good.

Rodder

iTrader: (2)

That's a powerglide/TH350/saginaw/muncie crossmember. The Th400 had a unique crossmember. If you modify a TH400 crossmember, also check the side-to-side position of the moment. Big block crossmembers had the mounting hole offset 1inch towards the passenger side. For a smallblock (including an LS swap), you'll want to move it back to center.

69LT1Bird

iTrader: (1)

I figured that was a given. You always have to verify the vehicle centerline to the drivetrain so the vehicle dynamics are not screwed up and you introduce vibrations and other issues.

wrathfullprimate

Ok ok but the ls1/4L60E does want to be in the center right?.. it looks that way to me anyhow.

So heres my plan.. move the cross member back to original holes. then cut it on the inside edge of the exhaust humps then fab a center section that goes down and back with a mounting plate in the center.