Piston to Valve Clearance Check - 351W

[Peldor]

I'm rebuilding my 1969 351W (actually, I'm almost done, I hope; -). ) I had just finished adjusting the valvetrain when I saw the note with the Edelbrock heads that said the valve clearance is not sufficient for
original pistons. I'm using Edelbrock 6035 heads with 2.02" intakes and TRW L2378 pistons. I called both companies and neither company could tell me for certain if these parts were a mismatch. I don't want to remove the heads and check the piston to valve clearance with clay. But I also don't
want them to interfere when I crank it up. Is there an easy way to positively check the clearance without tearing it down? Any suggestions for fixes (if it is a problem) without tearing it apart to machine the
pistons? Help!!!

[2bav8]

More than likely it doesn't have enough P/V clearance, sorry!

Unless you have a really small cam there's probadly going to be problems. You can hand crank the engine over to see if it hits, but that doesn't compensate for any valve float.

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[Clark Rodgers]

I have to agree, it doesn't look good for the stock pistons.I know you don't want to do a teardown but remember how much money you could lose if something hits!

[This message has been edited by Clark Rodgers (edited 07-29-1999).]

[Dave1]

Don't take a chance. You need about .100 clearance. I have seen guys put a piece of solder down through the spark plug hole and fish it over to where the valves are and turn the engine over ever so slowly till it squashes the solder, then remove and mic. But, if it was me headgaskets and intake are alot cheaper then bent valves etc. After you remove the heads check them with clay. Easy enough to do.

[90 lx conv.]

Hi, i was runnig a set of the TRW L2378 bored over .030" in my 351w. That particular piston is forged and is dished, i am not sure on what size the dish is however. I was using a set of GT-40X heads in which i had 1.94" intake valves and installed a set of 1.60's on the exhaust side. The cc of the head was 58 and my head gasket thickness was .030". I was running a flat tappet solid lift cam .555", .573" lift with a duration of 286, 292 and had no problems with clearance issues.
I would say that most likely you'd be ok, but to be on the safe side check with a local machine shop to get their opinion or check the clearance. I hope this helps, good luck!