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I'm in the process of freshening up my '74L with 15k miles, and I have a few questions.

I have read on this forum where the std 4v valves are prone to failing, is that the case for the last of the 4v heads with open chambers (assumed), small valves (assumed) and large ports (confirmed)?

I don't know whether to keep this standard low compression engine (and replace gaskets, seals, high volume sump, fully grooved mains, oil gallery restrictors, advance the camshaft 4deg, just minor work so as to not impact on originality) or if the valves are a potential issue, just swap it out for a 393C alloy head stroker (and store the original engine for safe keeping). As you would know, the Cleveland is well catered for here in 'the land down under'.

I'm not looking to race 7259, I'd just like to drive it spiritedly without a failure.

Any information or advice you can supply me with will be much appreciated.

Thank you,

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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? Smiler

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.

Thanks George.

I've been investigating a replacement engine (I don't like the sound of 'quick and dirty') and certain builders down here are 'grooving' the lifter bores! What would be the advantage with this, given nearly everything I have read is about limiting oil loss at the lifters? Also, where is the best place to make contact with Scott Cook regarding his alloy heads and manifold? Painted, these would be a 'stealth' upgrade.

Thanks again for your feedback,

Happy New Year!

There is no advantage to grooving the lifter bores at all that I know of. In fact, what you want to do is sleeve the lifter bores in order to restrict the amount of oil going into the valvetrain.

Lack of oiling has nothing to do with valve failure on the Cleveland. It is just an inferior valve design that the hydraulic cammed 351c's have.

Put a set of closed chamber iron heads on the car (as George recommended). That alone with perk the car up substantially.
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