Horse Sense:With the Z head, Ford Racing Performance Parts has come full circle. Back in the early 5.0 days, its first cylinder head was a streetable-but not emissions-legal-offering called the J302.

I have a 1971 Chevelle SS that I bought new. It is a 402 big-block, four-speed car with 3.31:1 gears and is stock. I want to freshen the engine up by increasing the compression ratio from 8.5:1 to ...