Reply to "'74 Heads"

To answer your question, yes the 1973 - 1974 motors have also dropped valves. Spirited driving has nothing to do with failure of the valves. Guys have had their motors drop a valve head while it idled in the driveway. Its a game of chance. A valve may fail, it may not. How lucky do you feel?

Pull the motor out, hone the cylinders and replace the dished pistons with a set of TRW flat tops, new rings, new Clevite rod bearings, and new ARP connecting rod nuts (the 351C's other weak point). Install a set of quench chamber 4V heads equipped with Manley severe duty valves, a Holley 4150 style dual plane inlet manifold (Edelbrock or Blue Thunder), QFT SS-780-VS carby, a breakerless or distributorless ignition upgrade and a Romac #0203 crankshaft damper. I can fairly well guarantee you the ring of the oem damper is no longer bonded to the hub due to its age. Advance the cam as you've suggested with a new Rollmaster multi-index timing set (set the intake lobe centerline at 117 degrees ATDC). Make sure the motor has the correct thermostat installed. Reinstall and enjoy.


Thats the quick and dirty, least intrusive and least expensive way to "fix", freshen up and pep up the Clevo. The increased compression, carburetor and ignition will make a big difference. The compression ratio will jump from 7.9:1 to 10.0:1 if the heads have 63cc combustion chambers.

-G