there are numerous cam selections out there..but for sure a solid ROLLER would benefit you...i DO NOT KNOW how far you wish to take this motor down or plan to buy new parts...But if you did you could make the motor a 383 stroker in place of the 355..this is 28 more cubic inches which would roughly give you 56 to 60 more hp. (2HP per ci)....you could also probably have those heads angled milled and get the compression up around 13.5 to 1....i do not know if you could get 14to1 compression or not but a good head man could tell you (Curtis)....with the compression up convert to alcohol and i would say you would pick up another 60/70 hp.....so from where you are now if you did all the above i mentioned i would not hesitate to say you could pick up another 120 to 130 hp...possibly more with the right combination.....
the type heads you have will make all the difference in the world...if you decide to go the 383 stroker route,,you might want to check into getting the 18 degree pistons along with some good 18 degree heads......going 18 degree you could make it an 800 hp motor without NOS,,NO PROBLEM.
AS THEY SAY MONEY BUYS SPEED...HOW FAST DO YOU WANT TO GO ??
your post was broad if you narrow up what you are willing to do i'm sure we can give you some good info on which direction to go.
Brian
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "