349 CI on the cheap

hi bobby
im really interested on doing this and while reading this i figured out why my engine runs like crap i only ported the intakes i want to find a set of 302 heads and have you work on them installing bigger exhaust valves and some port work question i have is will i have to get headers in order for it to work right or will my 70 hp manifolds be ok? also im running a M1 intake and a elderbrock 650 thunder series carb not sure on the bottom end it was previously redone before i got it but it does have .40 over pistons with valve reliefs i also want to change the cam in this aswell this is a street car would like it to have a rumpity,rump sound and still be dependable as i drive it back and forth to work