Custom rockers, fancy seats to go with your titanium valves ... Pretty easy to exceed $10k for a set of double throw down, nasty cylinder heads. Then set aside $4k or so for a manifold and around $3k for custom headers. Oh, and don't forget about $3k for a carburetor. And I saved the cheapest for last...custom valve covers. This is max effort stuff for either billet or cast heads. Then go collect your 4-digit dyno sheet