Well i was able to get some Canifield heads for pretty good pirce.
http://www.hi-psi.com/Corvette/Canfield/

But now i am starting to get little freaked out.

The reason i got such a good deal on them is because when we went to bolt them up on the car, the 4 top bolts would not hold the head, they would bottom out before touching the head.

The head was originaly oringed for boost application. The guy i bought the heads from had the oring milled down, they milled the heads .035 and milled the intake as well to make the bolts line up. We arent sure if the heads were milled down any before this, but i think its prety safe to say they were as the 4 top bolts bottom out before touching the head.

Will i have problems with piston to valve clearance? I am going to use the Felpro 1074 gasket, the bottom end of the car is stock as well. The car has a CC306 Cam with 1.6 RRs (230/244 ; 544/576 lift) on 112 lsa. How much can be milled down before you run into problems with the clearance, and how should i start checking the clearance.

Also what about the pushrods? Will i have to get some shorter ones if i decide to bolt the head up?


Thanks for help.

Marcin

 

As a matter of standard practice I've found it to be wise to assume that you WILL have problems with valve-to-piston clearance ANYTIME you modify the valve train. Not checking is a quick way to disaster.

Accurate checking requires a few specialized tools such as a dial indicator. a magnetic base, and light-weight checking springs. A simpler method involves carefully fitting a thin strip of modeling clay in the valve reliefs of the pistons, bolting on the head (with gasket), putting the valve train in place with zero lash, and turning the engine two complete revolutions. When the head is removed the clay should show impressions formed by the valves at their closest point to the piston. This method requires a little practice with the clay but it can tell you if a problem exists. If you're really careful it's possible to section a piece of the clay out of the way and measure the thickness of the impression to see just how much clearance you have. I never assume that checking just one cylinder is good enough. I've seen too many modified motors suffer catastrophic failure because it was too much trouble for the assembler to check them all.

You may need to replace the pushrods. They can be custom ordered to any length but they're available, over-the-counter, in .050 shorter (or longer) increments from most well-stocked parts houses. I'd check the clearance before replacing the pushrods.

Good luck.