Piston to Valve Clearance

[c1500sbc]

Well, the 383 is mostly built. Short of putting the heads on. Pistons are flat top with 7cc valve reliefs and are .010 in the hole at TDC. That leaves me with two choices for a head gasket. Either the felpro .039 or the .026. Obviously quench will be at .049 or .036 and compression ratio at 10.86:1 or 11.01:1 respectively. Camshaft im running is a mid .555 lift and promaxx 200cc cylinder heads. I'd rather get the quench down to .036 but i'm worried about piston to valve clearance. Any opinions? This will be a pump gas 93 octane motor.

[Nut124]

Did you test what the P2V clearances are? I would want no less than 0.080 axial, 0.050 radial but others will correct me for sure.

[SupStk]

Piston/Valve clearance should of been check during trial assembly. All the same I shoot for .090" on intakes and .125" on exhausts, with .050" radial clearance. You can run them considerably tighter but it reduces margin for error and cam tuning.

[CGT]

What are the cam specs?

[panic]

There's a range of radial ("ringing") clearance.
Heads with long, thin stems, short guides, and high lift need more, etc.
Heads with angled valve stems (almost everything Except Heron) also need clearance along the lift axis proportionate to the angle (15 degrees hardly moves, 45 degrees move more).

[ClassAct]

You can run the intake P/V as close as whatever your piston to head clearance is IF you have a belt drive or a good, fixed idler gear drive.

That means if you can run .040 piston to head clearance, you can run that for intake P/V if you have the above. If not, add .020 and send it.

I’ve run as tight as .065 on the exhaust, but I’d rather see .075. If you are that close and miss a shift, float the valves or something like that, you’ll bend the exhaust valves.

[ProPower engines]

Well, the 383 is mostly built. Short of putting the heads on. Pistons are flat top with 7cc valve reliefs and are .010 in the hole at TDC. That leaves me with two choices for a head gasket. Either the felpro .039 or the .026. Obviously quench will be at .049 or .036 and compression ratio at 10.86:1 or 11.01:1 respectively. Camshaft im running is a mid .555 lift and promaxx 200cc cylinder heads. I'd rather get the quench down to .036 but i'm worried about piston to valve clearance. Any opinions? This will be a pump gas 93 octane motor.

Thats not a ton of lift but have you check the PTV clearance at this point or just asking if it will fit??
I am guessing a 2.02/1.60 valve combo but have you mocked it up and done a valve drop check with the head on to see what you have before and after TDC at max lift.

If you check at TDC and 10 degrees before and after that should get you the details you need