You will need a new flywheel, specifically off of a 01-06 6.0 M/T or 99-06 4.8 M/T truck. The cranks are .400 shorter on the LS motors (with the exception of 99-00 iron head 6.0s), therefore your old flywheel will be too short. These can be had new for less than $100, whereas the Mcleoud conversion flywheel is $300+ The truck flywheel is .375 thicker than the old style flywheel, which is enough to make up the difference and get proper clutch adjustment. And the truck flywheel has a dual pattern allowing old style clutches to be bolted up.
I have all the parts minus the 4.8/5.3/6.0 to swap into my 67 while keeping the old 3spd column shift transmission, in the near future I plan on doing the same with a 6.0 and the sm465 in my 78.
There's a thread on pirate4x4 that has the part numbers for the exact combo needed to mate a sm465 to a LS motor.
