I just picked up a 2000 LQ4 6.0L and was just reading that because it has a longer crank I cant use a LS1 T56 but that some older trans bolt up to it. I really want the car to have a six speed so can I use an LT1 T56? Has anyone done this mod? Please let me know, I hope i didnt buy the motor for nothing!!!

I made a comment to that effect a few weeks ago, and the response was that might misalign the starter to the flywheel. But, no verification was provided that there would be a misalignment.

How could it not misalign the starter ring? The whole flywheel/clutch assembly would be moved back nearly 1/2" compared to where it should be on a LS1/6

It should align just like it would on an LT1. Maybe you just need to use an LT1 starter.

It seems to me like it should work, but I don't have the parts laying around to go check it out myself.

It would be great if it could work, because I still need to get the t56 six speed. It seems that LT1 T56's are a little more plentiful and a little cheaper than the LS1 T56's.

What about the starter from a 6.0L truck that used the spacer between the crank and the flexplate for the 4L80e? Or McLeod makes a flywheel that would solve it, but it's not the cheapest solution.

The clutch setup is completely different between the two, flywheels are different...

you would have to swap the bellhousings to use the style of throwout bearing/slave cylinder that the LS style T56 use as well.

Okay, I don't have any dimensions to back this up, but it seems to me that:

'99-'00 LQ4 engine
LT1 flywheel, clutch, bellhousing, T56 transmission, starter

Should mount up and work together.

And I could be completely wrong.

Or:
'99-'00 LQ4 engine
LS1 crank, flywheel, clutch, bellhousing, T56 transmission, starter

I don't think anybody would argue that would work.

Just not for sure if an LT1 flywheel will bolt up to an LS style crank. I know that a buddy tried to put an LT style T56 behind an LS1 and it was going to be more trouble than it was worth, swapping out the input shaft and so on with it.

Agreed the LS1 T56 isn't a good choice behind an LT1.

And you might be right about the LT1 flywheel on an LQ4. You'd have to neutral balance it.

Simple answer is to get an LS1 crank and T56 stuff.

Playing with cranks or engines is dumb, there's too much money involved. And the T56 you have is the T56 you have. So it's just a matter of choosing the right flywheel, the right starter, and connecting the throwout correctly. No need to overcomplicate it.

Except he doesn't have a T56 yet.

Changing the crank is probably the best solution, Im going to use a stock crank so it should not be too hard to find a later version.

any body ever figure out if this works. Is the main question just will the lt1 flywheel bolt up. Im good friends with the junkyard so maybe i can test fit my lt1 flywheel on one of their motors.

i know this is a really old post, idk if anybody found the answer to whether you can or cannot use a lt1 t56 trans in a 2000 6.0 truck engine.
i have both the lt1 with the t56 and a 2000 6.0L i will be taking the flywheel clutch assembly and starter of the lt1 and trying to meet them with the 6.0 and hope that the pilot bearing and everything else works without changing the input shaft or bellhousing

The starter ring is the biggest challenge. If the extended flange crank puts the LT1 flywheel in the same location as the LQ4 flexplate, then you're golden

Dont worry about the input shaft length. Use a LS2 CTS-V pilot bearing to catch the input in the large recess of the crank

You probably could retain the LT1's oddball pull clutch, but HTOBs are quite nice. If you make an adapter plate to hold one to the midplate, I would try that. IIRC, Using a LS1 clutch, the LT1 trans needs to be spaced back .125" from the block plus the thickness of the adapter plate for the HTOB

Custom flywheel. You could ask someone like Mcleod if they have developed one for it.

You'd need a flywheel drilled for the LS crank pattern. The crank with the CTS-V pilot would make the LT1 T56 too long if the LT1 bell is used.

I am saying no more today but you can use a push clutch on an LS with an LT1 input T56 trans. but modifications need done.