68 SS

iTrader: (23)

I had some one on here tell me that the crank flange is .400 longer on the 99 LQ4 6.0 truck motor and that the M6 will not work? I thought all the cranks were pretty much the same except the bob weight hence the different part numbers on the cranks?

devilsalmostfree

iTrader: (28)

the_merv just put n m6 in an lq4, its up & working, send him a pm, he'd be happy to help ya!

jmm98LS1

iTrader: (28)

What you were told is correct. The rear crankshaft flange on '99-'00 LQ4's is longer to mate up to the 4l80e. This means it will not bolt up to a t56 or 4l60e. Starting in '01 the LQ4's got the same shorter cranks that the rest of the ls motors use and a special adapter flexplate with a built-in spacer was used with the 4l80e. These later cranks work with the t56 and 4l60e.

trenth48

I am in the same situation, I have a 99 6.0 and want to put a t56 behind it. Is there any way of doing so without changing cranks?

jmm98LS1

iTrader: (28)

You *might* be able to find a machine shop that can turn down the rear flange to the same thickness as the shorter cranks.........dunno if that's a very cost effective solution though. Otherwise you have to change cranks. I picked up a low mile LS6 crank for $150 bucks here in the classified section for my 370ci.

Billy M

All Gen III/IV cranks are offset .340" as apposed to the Gen I SBC/BBC from 1955-1997 which were .740" a difference of .400". Mcleod offers a LS based flywheel with .400" added to the face to give you the same offset as a Gen I setup. Part Number is 460535

Project GatTagO

iTrader: (7)

The 99-00 truck engines already have a crank that has a bigger offset! Adding your flywheel will make the swap even worse.

Andrew

Billy M

I guess I misunderstood what he needed.