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Original Message
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| They will leak if you have the wrong type of heads |
| By Dave Shoe - 03/12/2003 8:34:41 PM; IP 12.104.160.195 |
The secret to getting Fe heads to seal lies in the fact that they have two different exhaust port positions, and no one has EVER written about this issue, except in the forums.
The emissions era of 1966-later is when the small intake runner showed up on many/most FE heads, and with the small "velocity" runner came an exhaust runner which was 5/16" lower than all previous FE heads. The dimensions of the port were the same, but they exited the head at a lower position.
To confuse the issue, 427 heads, 428CJ heads, and the C6AE-R head casting (found on maybe 1/3 of FEs in 1966-67 only), kept the large pre-emissions intake runner and higher-exit type of exhaust.
The C6AE-R was sorta special, in that Ford cast an little dam into the outermost roof of the exhaust port to prevent leaks across the top when used with 390 Fairlane/Mustang exhaust manifolds (which only fit the late-position exhaust port). Note that removing this little dam with a grinder will yield the early position exhaust runner.
Hooker only makes headers whech fit the early style of FE head (by extension, Hookers will fit C6AE-R, 427, and 428CJ heads beccause they retain the early position), but Hooker doesn't advertise this limitation and will sell you headers that mismatch the head and leak to high heaven, since the header gasket is sealed by the weld bead of the header pipe, and the weld bead can't crush against the bottom of the port if the port is lowered 5/16".
FPA is the only header manufacturer who understands the FE exhaust, and if you properly identify your engine to them you can be assured the headers will fit, flow, and seal really reliably.
Note that emissions-era heads typically have casting numbers of C6AE-J, -L, -U, -Y, C7AE-A, C8AE (no suffix), C8AE-H, and D2TE-AA. I think this covers about 99.999% of the low-exit head castings.
JMO,
Shoe. |
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