My home inspection of Speedmaster heads

The big thing with Isky tool rooms is the endurance testing they go through
Ran a set for 7 years on a 7500 rpm every lap motor( roller cam) and they still tested good.
Good springs are a GOOD investment
Agree. Record setters arent using your average hot rod parts. You can spend 2k on isky valve train fairly quick. Quality, reputation and history.
Everything has its place.