have been pondering

[sledneck07]

has anybody had the heads on their 4.0 milled down .010? i got a buddy who races at the local track and said that was a good power adder. also would a stock bottom end hold up with the increased compression? also what about valve clearence?

 

[Mechanickid]

0.10 doesnt really sound like enough to make much of a difference.

 

[turbo cat]

The 95+ casting heads will raise compression as they have smaller combustion chambers. Don't waste your time milling the heads down not to mention the oem ford heads have cracking issues that you may have heard of and milling them wouldnt help. Even if it was worthy of milling it would be smart to buy a set of aftermarket replacement heads that take care of the casting issuez

 

[Big Jim M]

It would be good to remember that once milled they ain't NEVER going back to stock! So it would behove you to enter these waters cautiously! Using the proper set of heads, if available, is always a better route. Changing the compression will change a lot of things besides possibly adding a bit of HP.
Big JIm