Do they even make 720's anymore? PTE makes 780's... Denso maybe?
400hp on a 20g would have to be around 25psi... Thats alot of boost on a stock block with an AFC.. Not saying it cant happen if you know what your doin..
If you have an e-prom, you can have it socketed and have a chip made for 550's to give you the curve you need to dial them in on the afc... An AFPR will help you too...
Good luck
95 AWD-auto
EVO3 / 450cc / 255pump / Hard pipes / MLS-ARPs / 3" c-b .
Precision Billet Converter 3500 stall/ IPT end clutch kit/ IPT valve body.....All on the way....
DSM LINK is next..