Originally Posted by BUP

if you are going to do a ground up build I would move away from the 496 platform all together. The stock 496 GM block nor the 496 crank not hold up to big levels of power and tq. The intake and heads are limiting factors as well.

Again if a ground up build, I would move on and away from the 496 getting a dart Big M block and and strong crank for a 565 or something along those lines that would offer better longevity pushing that amount hp / tq. Some high performance engine builders look at the 496 as the red headed step child engine and do not what to mess with it for big power gains..

Also there is alot more performance part upgrades in the history for the old standard big blocks than the 496 would ever have, Plus so many builders whom know the old standard big blocks inside and out compared to the 496.

from experience and reliability, the 496 is best suited in OEM stock form.

Originally Posted by Ryan00TJ

The OP already has a forged Raylar stroker rotating assembly and Raylar cam/heads. He's committed to the 8.1 platform. Your mainstream engine builders shy away from the 8.1 due to their inability to tune a modified setup. Whipple and Precision Marine are the only two shops who can modify PCM555. Tuning is the biggest barrier on this platform. Much easier/cheaper for them to build/tune an earlier gen bbc.

The stock 8.1 block is bore limited to about 4.280". 4.290" if you want to push it. The aftermarket blocks allow you to really open up the bore and power potential.

https://youtu.be/0W3fVh-rIhw

Ausscarab, Your stock closed cooling heat exchanger will not be adequate with 800hp. Look into upgrading to a SenDure #15006-1-5. Its a 5" heat exchanger that is plug and play. Whipple recommends it.