Classic/Antique Car Repair: fuel pump, small block chevy, roller rockers
QuestionFor a 327/365hp Corvette engine, what would be the recommended pump pressure and gph? The old books call for 5 to 5-1/2 psi, but does not provide the ghp. Also, if you bore an small block chevy .060 over, and switch the stock rocker to roller-tip rockers, how does that affect the overall horsepower? Thanks!
AnswerOne of my old tune up books lists the minimum flow rate for the fuel pump for that car at a pint to a pint and a half in a minute. So from there do the math. As for the roller rockers increasing horse power, the rollers themselves will not increase horsepower a measurable amount when used with a stock cam. Again the increase in the bore size in itself will only increase horsepower a very small amount. But when modifying an engine it is the cumulative effect of all the changes that increases horsepower. The roller rockers will decrease friction and allow for a heavier valve spring without a lot of wear. And a heavier valve spring is needed for higher RPM operation, especially with a high lift cam.
After I sent this, I went back into one of my old engineering books and checked. The design parameters for this sized engine was a minimum of 10 GPH. I guess that I have been away from teaching automotive tech and design too long to remember everything.