Well as I try to point out I am just getting started. As for stock handling 500hp, I am in planning and experiment stage. After hearing so many horror stories about rebuilds yet I have rebuilt several 231/3800/3300/GN 3.8 and had no issues.
The theory is find different short block/engine, and get it running first and for most.
I have few pieces from my Regal that fit and I also have my Olds that needs work, and other projects lacking attention. The DHP is to just get started, and allow me tuning for when I Supercharge it. Found good deal on zzp intake that allows me to use NA engine. And found wrecked GTP and one GTP Comp G minus engine! Just my dreams out strip my funds.
Trans options are countless. Time will tell.