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Old 12-05-2024, 01:02 PM
mgarblik mgarblik is offline
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Just a little "heads up" for the Speedmaster head guys. Had a student bring in a new set of Speedmaster heads for a big block Ford last night. Took them apart to inspect. All the intake valves were very tight. Only .0005" clearance. Exhaust were pretty tight too. .001"-.0015". The valve job was just horrible, worst I have seen on Chinese aftermarket heads so far. We lapped some for a look. Intake seat was very wide, .070" and placed way down on the valve face negating about .090" of the valve diameter. The exhaust was a decent width, .055" but also extremely low on the face, all the way off the face toward the stem! Although they would bolt on and run, probably giving up 30-50 HP from the awful valve job. We are going to hone and fit the valve guides and re-cut all the valve seats to at least make a decent set of heads out of them.

So my advice is to disassemble your new Speedmaster heads and lap the valves to at least verify where they cut the seats for placement on the valves. The Pontiac set we checked a couple weeks ago were much, much better but the work may be inconsistent. Check, don't guess.

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