lift question

[Sleepychallenger]

On your normal 70 383 hp, how tall lift on the cam before you have to start worrying about hitting a piston...just in general? I have stealth heads and a cam under .500 But was thinking g of going above 500. Thanks for any input

[73restomod]

Anything above .500 and you need to check piston to valve clearance, just to be on the safe side.  Main reason is depth of factory piston reliefs.

[Chryco Psycho]

Usually you are good to .520  but worth checking above .500

[Sleepychallenger]

So pull the head, tdc, play doh on top of piston, then...? 

[HP_Cuda]

PTV baby!

[Sleepychallenger]

PTV?

[HP_Cuda]

PTV = Piston to Valve clearance

[OUTLAW]

I think what he is aking is what next. The way I do it is: pull the head and put play-doh ontop the piston and I spray the valves or play-doh with cooking oil so the play-doh doesnt stick to the valves then Put the head on with out headgasket and tighten lightly then rotate 2 complete revolutions  then remove head and measure the play-doh. I slice the play-doh to make it easier to measure

[Chryco Psycho]

You should not have to pull the head , you can pull the valve spring & use a light checking spring & rotate the engine over & check how far you can depress the valve , but this is not as easy as it seems as the closest distance is usually 10* or so before TDC for exhaust & 10* after TDC for intake but eventhat can vary by a few degrees