O.k. I have a 68' 400 2-barrel motor that I was thinking about putting a 4-barrell intake and carb. on then I was thinking about putting on my #16 heads with d-port exhaust manifold's.I was told that I should put a mild cam in to.Until next year '05 when I plan on having another 68' 400 out of a g.t.o. really rebuilt for the bird.Now my ? is if I change the heads w/o changing the cam will this weaken the bottom end and by changing the cam will this weaken the bottom end.I want to add a some h.p. to this motor w/o spending alot of $$