Big Block Heads Milled??? - Moparchat

63Fury · #1 02-13-2008, 10:02 AM

Besides cc'ing the head is there anyway to tell if my 906 heads have been milled? How much can a 906 head be milled 0.100? How much will the intake face of the head need to be milled compared to the cylinder face? I thought it was .7 to 1 intake to cylinder in other words if .100 off the head would be .070 off the intake.

Any specs on how much milling reduces the cc'c in open chamber and closed chamber heads?

Thanks

Paul Precht · #2 02-14-2008, 01:32 AM

Mic the head by the spark plug area. If it's about an inch it hasn't been milled or very little. A .040" cut will drop it about 10 CC's. Cut the intake surface .0123 for every .010 you cut the deck surface of the head. If you cut more than .040", the end rails on the block should be taken down .017" for every .010" the deck is cut, Paul.

63Fury · #3 02-14-2008, 09:07 AM

Quote:

Originally Posted by Paul Precht

Mic the head by the spark plug area. If it's about an inch it hasn't been milled or very little.

So if it mic's out at .950 it has been milled around .050?

Quote:

Originally Posted by Paul Precht

A .040" cut will drop it about 10 CC's.

We are talking open chamber or closed chamber.

Quote:

Originally Posted by Paul Precht

Cut the intake surface .0123 for every .010 you cut the deck surface of the head.

So for .040 off the deck would be .0492 on the intake surface?

So if my compression calculations are correct if I have 8.8 and mill off .040 or 10 cc's ill get about 9.4. I can live with that.

Thanks

DartGT66 · #4 02-14-2008, 09:24 AM

About 10cc open chamber (for teh first 0.1"), and about 7cc closed chamber.

63Fury · #5 02-14-2008, 09:34 AM

great thanks

Paul Precht · #6 02-14-2008, 10:37 AM

.0042" per cc for open chamber, .0062" per cc closed chamber, .005" per cc for Max heads, Paul.

63Fury · #7 02-15-2008, 08:50 AM

Quote:

Originally Posted by Paul Precht

Mic the head by the spark plug area. If it's about an inch it hasn't been milled or very little.

I checked both heads and they mic out at 0.965 so do you think they have been milled?

63Fury · #8 02-17-2008, 10:23 AM

Upon inspection of the heads I found that the machine shop stamped 50 and 40 in the end of the head. I'm going to assume that would be .040 on the surface and .050 on the intake. Would that be a good assumption?

Paul Precht · #9 02-17-2008, 12:03 PM

Yes, thats what I always did unless it was just an .008" cleanup, Paul.

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