Well more specifically, I need to know if an LT1 T56 will fit behind a '99 or '00 LQ4, which is the years the blocks had iron heads and longer crankshafts to accept the 4L80E. It is my understanding from another person's trial and error test that the T56 from an LS1 car will NOT bolt up to the back of an LQ4 from a '99 or '00 truck, but that a 700R4 and TH350 WILL bolt up, which leads me to believe that a T56 from an older car (LT1) would probably work? Can anyone help me figure this out?


Or here's another scenario: What if I put a crankshaft and flexplate from an LS1 block in the LQ4?

 

Good thinking on that, i havent read about that, but its likely.

Your correct that 99-00 LQ4's will not bolt up to a LS1 T56.

Curious as to whether a viper one might. They have a .5" longer input that needs to be turned to fit them into an f-body clutch/pilot.

 

Well unless I find out for sure if there is a T56 out there that will work with this block, I'm getting my money back from the seller on Monday because he told me it was a 2001.

 

Ill dig around LS1tech a bit, ive got a sneaking suspision, if a LT1 flywheel will bolt up, it should work. The difference between the LT1 and LS1 T56 is the LS1 has a longer imput shaft, i would think this would cure the issue

 

I tried asking some people on LS1tech and haven't got a straight answer yet. I need to know by Monday because that's when I'm meeting the seller to get my money back

 

I edited my original post with another question.

 

LS1 crank and flywheel would solve your problems.

Speaking of which, ive got one here.

hahaha, sheldon

 

Sweeeet! I get to keep the block then you rock

 

hahaha, i try

 

so u have a 99-00 shortblock that u are trying to mate with lt1 t56, correct? usually lt t56 are assembled with ls parts to make work with ls.
and the lt bell houing will not allow the correct bolt pattern. the dowels on the ls block are correct for ls bellhousing. u can tell if u have a long flange, if the crank flange protrudes around .400 from the seal. if its standard flange, its dam near flush with the seal, maybe sticks just a tad.