All bronze OHV manifolds that I have re-conditioned were long, not short like the '40.
They most often were found upon '47 EL's, and they are also prone to horrendous casting porosities, as shown in the attachments.
Moldthread's cast PEEK seals are ideal, if your manifold spigots are pristine and of the original diameter.
Bronze manifolds are more malleable than even steel, and have nearly all worn or distorted with use. Therefore, they require swaging before re-cutting to accept a fresh seal of any material.
PEEK seals have proven user-friendly and reliable when properly re-torqued, and in the decade of their use, nobody has worn any out. They are re-useable as long as the spigots were pristine in the first place. Blemished surfaces will make impressions that can be sanded out for re-use, but naturally shorten the seals' otherwise infinite lifetime.
The bottom line with any manifold seal is to properly test it before risking the motor.
This only requires air pressure, soapy water, and a little patience: http://virtualindian.org/11techleaktest.html
Beware that barnyard tests give barnyard results; The porosities shown below could not be detected by spraying it while the motor was running.
The greatest obstacle to restoring intakes is finding a sealer for the nipple thread that not only resists today's digestive fuels, but tomorrow's.
Last edited by T. Cotten; 08-17-2010 at 07:47 AM.
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