Was talking to a few people and they said its not reliable. Others say they have made 700-900 WHP on them with out issues. What would EvoM and reputable shops advice be?

Does it depend on how light the rods are we are thinking about using aluminum rods for this R&R with HD Piston pins.

Not sure if to use 156mm or 162mm though.

 

I have used plenty of 64 cranks with no failures at 400-650 whp. Which is closer to 800 flywheel horse power.

An addition that I do to my cranks is lighten them up. I have part of the counter weights cut off then the crank polished and balanced. After that it is Nitrided. They key to this is to NOT knife edge the crank. The weights are designed to absorb harmonics from the rotating assembly. If you make when slimmer, you will remove the mechanical properties of the crank that assist in removing the harmonics.