Quote Originally Posted by Itoldyouso View Post
Ok, I'm dumb. What's an sb2???????

Don
(LOL)Don,
I was SOOOO glad to see you post this!! I had the same question and Googled to find that Chevy came out with a modified head design to cant the intake valves like a big block for better high RPM performance, specifically for sprint car and NASCAR applications (small block, second generation). When developed, the heads were the only thing special (as I understand), but later GM started looking at some internal mods to make room for bigger cam bearings, etc. Bottom line, it seems to be a derivation of the SBC, built for racing.
http://www.musclemotorparts.com/chevyheads.htm