BBC Heads which to look for
Hello, i have a 1990 GMC Suburban 7.4 TBI, it has always been a dog. I have had of for a couple years and it never had the grunt and torque of other older 454's that i have had, I have had the heads off because when i bought it it had lost a timing chain and ran valves into pistons. I noticed at that time how small the rect. ports on the heads were, they seem VERY small and restricitve. Well its time for a rebuild now and i want to change the heads and try and make a little more grunt for towing, any ideas what i need to look for for casting numbers, i dont mind having to change the manifold to an oval port if needed, seems lots of people are saying 049 casting. keep in mind it will need to smog thanks in advance