healeyboz said:
This is the email that I got from the head builder.
>The head I sent has been prepared for SCCA autocross regulations in D
>-Prepared. This is similar to the requirements for F_Production in road
>racing. The valves are the largest allowed. The springs are BMC ST
>heavy duty and are rated to 8400 rpm. The exhaust valves are Stellite
>high strength high temperature material and the valve seats are hardened
>for lead free gasoline. There is subtle porting and polishing. The head
>has been milled to bump up the compression ration about a half point.
Actually, in SCCA F-production, you are not allowed to run larger valves, 1.31 intake, 1.16 exhaust, and the valve spring were never made by BMC, but originally designed by David Tabor and made by Isky, since then several people have made theses springs, including past HP champ Wally Hicks, I sell Wally 's springs, but they were never made in England and way beyond what the factory or UK suppliers ever offered. As for compression ratio level used in SCCA F-production, I built heads on 1275 as high as 15.5 to 1, on 1275, higher on 948s. Oh and we don't run pump gas, more like 112-114 octane race gas, so no offense, but not much truth in his statement. Autocross and SCCA national road racing are two worlds apart.
Something always confused with our little cars, because of the rule formulas in SCCA racing, US builders have far exceed HP numbers of the UK builders. I tell my race engine customers, in a good SCCA or vintage motor, 80% of the components are US made.