Here's what I have. I have a 1979 350, Edelbrock600 cfm carb, comp 270h-10, new lifters, new springs, new double roller timing chain, holley street dominator 300-38 intake, and a new holley mechanical fuel pump. Should I keep my 350 heads or switch to my 305 heads? About how much would this combo be worth as far as h.p. ?