Milling heads.

[Doosterfy]

I'm using Stealth heads on my 440. It has Speed pro flat tops and the block has been decked for a zero deck height. I want to mill the heads but do not want to cut them to the point where milling the intake becomes necessary. Can anyone tell me how to determine how much I can safely mill them?

 

[805moparkid]

i would mock the heads up with head gaskets and then set the intake on without gaskets and look at you angles. then remove head gaskets (.020-.050 thick depending on gasket) that will give you an idea... for YOUR engine

 

[Doosterfy]

i would mock the heads up with head gaskets and then set the intake on without gaskets and look at you angles. then remove head gaskets (.020-.050 thick depending on gasket) that will give you an idea... for YOUR engine

OK, I did it. The used gaskets I used measured about .040. With the gaskets the intake fit well. Without them the fit was not so good. I've done some research and some people have milled the intake surface of the heads and were able to leave the intake manifold alone. I saw very little info about how to figure out how much to remove from the intake surface of the heads in relation to what gets removed from the block mating surface. I'm thinking about removing .010 to .020 from the block mating surface. If anyone knows how much to remove from the intake surface in relation to the block surface, let me know. I saw one person said 1 to 1, I.E. if you take .020 off the block surface, take .020 off the intake surface. Is this correct?

 

[IQ52]

For every .010" you mill from the combustion chamber side, you mill .0123" from the intake surface.

 

[moper]

What is the goal of the milling? Depending on the gasket you're already at 10:4. I'm not sure but IIRC it's something like 1 cc for every .008 milled on them. Id there a target you're looking for?

 

[Doosterfy]

OK, so its remove 123% form the intake surface. Thanks, that helps alot. The goal of the head milling is to 1) make sure the heads are perfectly flat and 2) increase the compression ratio. The cam I'm using has 254 intake and 260 ex duration @ .050. Thats not huge but big enough where compression becomes important. I'm working with a motor I had bought already built for a bargain price and its turned out to be no bargain. If I were to do it again I'd start from scratch and would have used lighter weight pistons with a dome to get about 11to1. I hate low comp. motors. I checked the valve to piston clearance and there is plenty of room so I figure might as well mill them and gain a little more compression. I'm not expecting to make that much more power, its the throttle response and part throttle torque and the attitude of the motor that I like about higher comp.