you don't "need" valve guides, but why not put them on??
Whoever is doing your heads will know what
you need.
You should have a mild port job b4 putting them on.
Deck them to raise compression, and also have the exhaust side cleaned up.
Probably cost about $200, and will get an honest 15-20 more hp.
if they are aluminum, probably 25-30 or 40-50 hp gain.
iron probably 15-25 or 30-35 hp gain.
(stock or ported)
depends alot on your mods now.stock heads are a big bottle-neck
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