Whereas most cylinder heads must be "hogged out" (ported, polished, etc.) before they're ready to do battle, there are times when just the opposite procedure is necessary. A good example can be found ...

Chevy fourth generation aluminum big-block head is readily i.d. 'ed by "bow tie" emblem and new square exhaust ports that exit ¾ inch higher than previous D-port design. You'll have to drill new ...