I am building a 75 440 engine w stock pistons and a CompCams XE268H.

I found a good deal on a set of 452 heads all set-up and ready to go. One problem, I did a dry fit onto the block and found that the heads are milled about .125. What is the advantages to doing this? Also, the intake will need to be machined. What should I do about push rods and valve to pistion clearance?

Thanks for the help..

How did you tell that the heads have been milled?? Especially how much? Rule of thumb being to mill the intake side of the head .0123 for every .010 off the face to keep everything in alignment with out having to re mill everything if you want to mix or match down the road. If you mill the intake it makes it basically usable only on the application using the same heads that it was milled for. where if you mill th e intake side accordingly you can use either the heads or the intake down the road or sell with no further milling nessessary.

Don,

IIRC the pad is 1" thick on the BB heads as stock, pretty easy to tell if they have been cut.

i dont think ive ever heard of any being cut that much. i think at about a .090 cut it ends up a closed chamber.

I put together my '73 440 with the stock pistons that ended up right around .098 to .10 down in the bore. I am actually running the same cam from Comp Cams, the XE-268H. But I am using a set of 516 Closed chambers with the bigger valves (hardened seats) from my 346 heads. I want to say I had about an 1/8" of valve to piston clearance at the nearest. I would have to say that you would be opening a can of worms with those head milled that much. I would agree, - PASS

Milling the heads that far is about the only real way to gain compression on the mid 70's 440's with their stock pistons a mile in the hole. That's why it would have been milled that far. I've talked to plenty of people on this board who've done that, and it does work. Though the chamber shape is very poor because so much of the cylinder wall is part of the chamber. Also, milling that far supposedly makes the heads more crack-prone.