Fellas,
I placed my order for my Canfields and should be receiving them soon ($1100 assembled, roller springs, from Howards).

Here's the deal: I'm going with a solid roller cam, but piston to valve clearance MAY be tight with this motor. It probably wont be, since the valve notches are fairly deep and the slugs are .024" down the hole.

BUT, I may be running .590" lift depending on the cam I choose. To me, thats a lot!

Long story short, I want to be reasonably confident about the PV clearance BEFORE I order the bumpstick. Do you guys know of a way I can accomplish that?

I'm worried if I install the cam, find out there isn't enough PV clearance, and then can't return the cam because I've installed it. Or am I putting too much thought into this?

The cam lift won't affect the p-v clearance that much, duration has a much larger effect. Being 24 down in the hole makes no difference if you maintain the proper quench height with a shim head gasket.
The manufacturer of your pistons and cam should be able to give you a good approximation of the clearance. Some post a chart of the valve lift vs crank angle so you can calculate the closest point and measure the clearance.

I mention they were .024" down because it's difficult to find a good 4.200" bore shim head gasket. Or else I haven't found one yet, so I'm using .039. My block is o-ringed anyway, so I need the "fire-ring".

Really? Nobody?

Valve notches in pistons are ~.220" deep, by the way.

matt, the best way imo is to do it with a dial indicator. you put light springs (actual checking springs, very light) on the intake/exhaust of at least one cylinder, and set up valvetrain as you would run it, lash etc. set your gauge up on the retainer, then using a degree wheel, bring your piston up to tdc (during the overlap period, when both valves are partially open) and then press the valve till it hits the piston. watch the dial, and see what it travels. record that number. then go atdc untill the distance gets larger (it will get closer first probably), and record that number. i went in 5* increments, then less as it increased/decreased. then do the same for btdc, and record those numbers. subtract the numbers from gasket thickness to be used (do this w/o head gasket, btw) thats your p to v for whichever you do, intake or exhaust. its the same procedure for both.
did that make sense? its really very easy, and if you run tight p to v, its very accurate. you can also do a similar method with clay, but when you are closing in on .100 or so with a big cam, clay is too hit and miss, imo, although many people still do it that way successfully.
just let me know if i can clarify anything for you, good luck with it graemlins/thumbsup.gif