rookie ques bout piston2valve clearance

most piston manufacturers will tell you how deep the pistons are cut to give you a pretty good idea of how much room you have to play with.

The only true way would be to measure it yourself

email or rather pm Mark Oneal over at hardcore 50. Hes always on there.

Others can give you an idea what their clearance was on a similar combo - if they've measured it. Most haven't. The problem is that a combo with identical components can have significantly different clearances. The only way you'll know your exact clearance is to measure with your cam.

There are some ways you can mitigate the uncertainty, but you'll have to take some measurements. First, you'd need to go ahead and get your heads, and pistons and do a mock up install to take some measurements - no way around that step. You'll need a degree wheel, and a dial indicator and a positive stop (to find actual tdc) - the same equipment you'll need to degree your cam or measure your p to v, so you're gonna need it eventually anyway. Basically, you'll need to remove two valve springs (int/exh for #1 cylinder), and using the degree wheel and dial indicator, measure how much distance there is between the valve being closed, and the valve touching the piston at 5degrees btdc, at tdc and at 5 degrees atdc. If you provide those measurements to any of the custom cam designers out there, for a given rocker ratio they can compare that to the lift at the valve at the same points (-5, 0, +5) -- the difference between that 'drop valve' measurement you made, and the lift of the valve at the same point is a pretty good approximation of your p to v clearance; so they can come up with a cam that should give you the clearance you need. You might be able to get the same info out of the tech lines at some of the cam companies -- but I wouldn't hold my breath. Most of the folks I've talked to are more marketing folks than technical specialists.

Give DSS a call, they have stroker kits in stock that have pistons that will clear your exact combo. I gave them a call, told them what I had, and they had the right pistons on the shelf. Got them in a cpouple days, and no clearance issues at all. Very pleased, especiallt after the tech guy at Summit told me no one makes pistons to clear 2.02 valves in sbf. Dumb@$$.

Haven't had it to the dyno, but I figure it should be good for around 330ish at the rear wheels. I like the combo, as it's gone deep into the 12's with spray on street tires, but I just scored a 351 block from a friend of mine, so I'm off to build a 392 for next year. Car's mad fun as it is, but my friends LS1 is just god aweful fasft, and he's looking into a 427 block now. I can't let him stay ahead of me like that .