a few more head milling questions

[stinger]

I have a set of 452's that are currently at 88 cc's,checked them.I'm considering haveing them milled to get to 80 cc's.what's the math for open chambers? 0.002 or 0.004? or better yet what would need to be done to drop down to 80 cc's? still up in the air if I'm going this route,probably not if the result is more headache for the half point gain I'm looking for.

this also brings up another question,how well do the MP steel shim head gaskets seal? the block was not decked as far as I can tell.
Thanks!

[Kapteenikosmos]

The numbers are bit incorrect there. I milled 1.2 mm (0.0472 inch) from my heads and that is equivalent of about 12 cc decrease in the combustion chamber size. The decrease in cc can be easily calculated for open chamber head if you just measure the diameter of combustion chamber and calculate it from there. When the heads are milled so much that the quench area starts to emerge, then the things get bit more complicated as far as it goes for the decrease of chamber size.

From the intake sides I milled 1.55 mm (0.0614 inches). That's calculated from the v-angle of the block and the angle between deck surface and intake surface (that one is 80 degrees). I have a great table for the milling values at home which I can post here today when I get there after work.

[stinger]

here's something I've found http://www.mopar1.us/mill.html

[Kapteenikosmos]

That table sounds correct, for open chamber head the value of 0.0042 inch per cc is the one you should use for 452 heads.

[71chally416]

Cutting them .034" should pose no problems if that's the amount needed. And I've used the steel shim gaskets many times back in the day. Just use some kind of sealer on them like the spray on stuff.   

[stinger]

Thanks guys,one more question.if I mill off .034 should I take off the proper amount on the intake side.I've asked some people who have had this done to there heads and I get conflicting opinions on wether I should or not. I'm thinking I would.

[71chally416]

I usually lay the heads on the block and see how the Intake fits before cutting the manifold surfaces, but if the Intake fit right before the head cut (bolt holes were centered) go ahead and get that done at the same time. If you're not sure you should check first, and don't forget to use head gaskets the same thickness or use some shims under the heads the same thickness of the compressed gaskets.

[stinger]

thanks for your help chally!

[71chally416]

Just remember the first rule with machine work. You can always take more off but you can never machine it back on.

[stinger]

Just remember the first rule with machine work. You can always take more off but you can never machine it back on.

yeah,I'm still considering other fators such as p rod length,sealing problems and the fact that I have no quench to begin with...030 off the heads will give me a better option as far as head gasket selection goes..

[71chally416]

You can always shim up the rocker shafts. Mancini sells some nice shims if you need them.