Hi Guys... this thread seems to have died last Sept, if anyone gets this please let me know the outcome of the situation you guys were talking about. I think I have an alternate solution... the LS1 crank is 0.400" shorter than old school SBC's... the stepped pilot bushing that is referenced in the thread is needed, but I believe you can simply apply the GMPP #12563532 spacer to the back of the crank, bolt on your existing flywheel/flexplate and clutch setup. If using hydraulic throw out bearing all should be ok.
So, for $50 (Jeg's price) the spacer is a bunch cheaper than a new flywheel/clutch/etc.

 

That spacer is designed for automatic flexplates so that the torque converters on older TH350 and TH400 transmissions will bolt up. The bolt pattern on Gen I SBC flywheels is different than on LSx engines. Gen I SBC actually had two different patterns, older than 1986, and 1986 and newer. The diameter is also different so the starter won't engage.

All you need to do to bolt up a D&D Viper T56 to a LSx engine is follow the same procedure as a TKO, Richmond, Muncie, or T10. An extended pilot can be used, but a more elegant solution is to use the LS7 pilot bearing that sits in a recess further towards the rear. There is some detail more details in my build thread. Link in sig.

Andrew

 

do you think this pilot bushing would work instead of mcleods?

http://www.speedwaymotors.com/Chevy-...hing,6974.html

i asked the guys at speed way for the dimensions, they said this:

0.590" ID
1.092" OD
1.008" LONG

im not sure if thats right because i thought a stock bushing was longer than that?

 

Some issues for sure on the swap.
I have both the LS1 6 speed and the LT1 transmission in my shop.
The Belhousings are different lengths from front to back.
The input shafts are different lengths.
The aluminum section of the transmission that the input shaft goes through are different, this is to accommodate the hydraulic throwout bearing as it pushes against this plate. To keep it simple I purchased the second transmission for the conversion and am planning on selling the lt1 transmission.

You can go either method, but I would be ready to mock it up when parts arrived and confirm their return policy before ordering anything. The hydraulic clutch should be easier in a transplant.
Best of Luck
Rick

 

Didnt read much of this thread, well really any of it, been drinking... but... I'm running an LS1 D&D Viper T56 behind my 2000 Fbody LS1 and i bolted it right up to stock 2000 LS1 pilot bearing. LT1/gen1 SBC style engines require a .400" longer crank. I dont know that you could space the LS1 flywheel to get it to work. The 99 6.0L Ls1 i have sitting on my engine stand has a .400" longer crank though and i've been contemplating mating an LT1 t56 to it.