Nailhead Camshaft Lift - What's the Limit?

[Mark Ascher]

I'd like to get some opinions on this thread on V8Buick:

http://www.v8buick.com/showthread.php?t=241729

Since I have a cam in the car that is over .500, I'm curious. I bought the cam and all valvetrain parts from Carmen.
Pistons are stock compression Kenne Bell.

Mark

[WkillGS]

I'm using a Poston NH400 cam, Tom's roller rockers, and replacement valve springs from Clevite and Isky. Lift is close to 0.550".
Coil spring bind is not a problem, but I did replace the valve guides and had them cut down for clearance.
I'll have to dig up my notes and find the exact numbers on the stock guide clearance.

[Mark Ascher]

Walt,

The "stick" cam I got from Carmen has a net .485 on the intake and .515 exhaust.
I can post the rest of the specs if you're interested. We put bronze guides in, and I know
my builder had questions on doing that that he eventually resolved with Carmen.

The darn thing runs, but the question posted had me wondering.
Thanks!

Mark

[telriv]

Never happen on the net. I would almost be willing to bet that if you actually measure lift at the valve you will find you MAY have .430" give or take. The higher you go on lobe lift of the cam the less ACTUAL lift at the valve you get. The ONLY way the ratio is 1.6 is with no more than a .250" lobe lift. At a lobe lift of .303" & .322" the ratio will be closer to 1.4-1.5.

                     Tom T.

[wildcat65]

Hi Mark, who did your heads?   

[GranSportWagon]

Since someone brought head work, Mike Lewis in Fresno, Ca ( Protech Racing, http://www.protechracing.net/index.html) is fast becoming the resident Nailhead expert porter. Not cheap as it is very time consuming work,  but the end product looks like art work.
Mike S