milling 440 heads

[carolina440racer]

how much can you safely cut off a set of 906 heads to increase compression? I am going to use the forged flat top piston from Summit in their rebuild kit. (I think they are rated at 9.0-1 on 78.5cc heads. What are the stock 906 cc's? I have seen people say .060.

[rat roaster]

I have seen them cut so they look like closed chambers. No problem getting 78 cc or even 75 cc. A stock 906 is in the mid to high 80 cc range. I had a set milled .050 once that I had head gasket problems with ,so make sure the shop doing the milling is competent and has good equiptment.Right now my 915s are .045 and work fine. If you are not using adjustable rockers you will probably have to shim your rocker shafts. Instead of milling so much buy a set of pistons that have a quench dome on them set them at 0 deck or .010 down. Saves alot of hassel on intake manifold line up and shimming rockers.Piston to head clearance no less than .035 on a tight clearance(piston to cylinder wall), I preffer .045 to alow for piston rock as the motor miles out.

[This message has been edited by rat roaster (edited January 07, 2001).]