Thread: 302 Rebuild
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Old 07-08-2011, 08:16 PM
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bobcowan bobcowan is offline
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Location: Colorado Springs, CO
Cobra Make, Engine: Backdraft, supercharged Coyote
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You're going to put a new top end on a 20+ year old bottom end. That's fine if you plan on doing this job again in a couple of years. If you want to do it once and forget it, you should consider a new bottom end.

Twisted wedge heads make good power. But sometimes need special pistons to match the differant angle of the valves. Not always, but sometimes.

Better heads with bigger valves and a matching intake for air more flow; can be an excellent idea. Planning on a new cam? If not, you won't see the full potential of the heads and intake.

Stock iron heads have a combustion chamber of about 60-62cc, and you get a compression ratio of about 9:1. The TW heads have a chamber volume of 64cc exactly. Bolting them on to a stock bottom end will cost you compression. Compression is what makes power. Consider a head with a smaller chamber, like 58-60cc. If not, be very carefull about cam selection.

Maybe the $$ don't match up where you live. But here in the USA, it's usually quite a bit cheaper to buy a ready built crate motor, rather than try to rebuild what you already have. A lot faster and easier, too. Unless, of course, your buddy owns a machine shop and will do all the work for a case of beer.
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