[oldman]

AFAIK GM had an issue with the lighten LT1 crank and hence the LT4 has a solid 7&8 rod journal or "pin" as well as a fillet radii vs undercut ends, different steel (that is from memory. I'll cut and paste below). So HP probably is not the limiting factor but rather torque. At the stock LT4 torque level GM felt the LT1 crank was inadequate.

IMO a real crank is needed at 750 ish HP and / or 650 ft-lbs. I did not do it and I feel that will be where my engine fails if it does fail before 100K. GM felt a better crank was needed at 650HP and /or 650 ft-lbs

Any build I talk about should have a MTB failure of 100,000 miles, drive it like you stole it; also note that a manual is probably harder on the rear rod journal vs an auto.

TSP aftermarket stroker is rated upto 950 HP: https://smgspeed.com/product/tsp-for...t-sump-oiling/


Rotating assembly – Each component of the rotating assembly is unique to the LT4 to support the cylinder pressures the boosted engine is capable of generating, as well as the unique requirements for a lower compression ratio. Elements include:

A 1528MV forged steel crankshaft with tungsten balancing inserts, ground pin collars and intermediate pin drills for rods 1-6
A lightweight, forged 6061 aluminum damper with a T6 anodized hub and an iron inertia ring (the LT1 uses an iron damper)


If I ever go into my engine again (other than change valve springs), I'm going LT4 or better crank, LT4 damper, and look into the best trust bearing upgrade, and a Zl1 clutch, oh and I'd stud the mains (already studded the heads).