Hello there. I have posted before in reference to putting a comp xe268 cam in my 81 vette, and needed some opinions. I am getting rid of my stock 76cc chamber heads, and I am considering these heads that my buddie just had done, and milled. The casting numbers are 3973370. I was hoping these would be better than the smog heads that came with my 81 vette. Let me know what you think. They are $250 completely done. Think it will help my performane any??