I currently have a 381ci sbc in a mustang actually just got done with drag week. Car ran without any problems actually got 2nd place to a really fast pinto! I now have a gt4788 turbo on it I just want more! Thinking of going with twin 6765 billets or the 76mm billets. With the gt4788 on it it only makes 24 psi on kill and I just would like to be able to push it to 30-35 psi if I need to! The heads are afr 210's cam is .630 .630 252 248 on a 116. I am just worried that if I put 76's on it it will not spool for crap! compression ratio is 8.75-1 bore is 4.020 stroke is 3.75! Thanks for your info!