440 deck milling limits?

[polkat]

How far can you safely mill 440 block deck surfaces? By safely I mean retaining strength et all. And should you then mill the manifold for alignment as you would when milling heads? For example; is it okay to mill the deck surfaces .030"?

 

[Cranky]

.030 most likely will be fine. It's not hard to visually take a look at the thickness of the deck through the water passages. Core shift can play a part but I've never seen a really thin block deck that was still stock. Sure, anytime you mill the block or heads, you should at least check the fitment of the intake and pushrods. I like to do a mockup before cutting the intake faces after doing any block or head milling because factory tolerances do vary.

 

[Meep-Meep]

I have info that says for every .010" removed from the head surface you should remove .0123" from the intake surface. I imagine this can apply to the block deck as well.

 

[Cranky]

I have info that says for every .010" removed from the head surface you should remove .0123" from the intake surface. I imagine this can apply to the block deck as well.

That's the rule of thumb but not all blocks and heads and intakes are created equal....that's why I mention doing a mock up to make sure what needs to be done. I've actually had intakes (aftermarket mainly) fit better after taking a significant cut on the head's deck surface. The rule of thumb is mainly for stock parts but who is using stock parts when they start milling and decking? Some I'm sure but not most. Besides, most of the time, taking .010 or even a little more won't affect things much at all if any and will sometimes make things fit better. After milling, mock it up before cutting the intake surface because once the cut is made, the metal is gone and you can't put it back without major surgery. Nothing in this world is perfect and Mom Mopar wasn't any different...

 

[Meep-Meep]

That's the rule of thumb but not all blocks and heads and intakes are created equal....that's why I mention doing a mock up to make sure what needs to be done. I've actually had intakes (aftermarket mainly) fit better after taking a significant cut on the head's deck surface. The rule of thumb is mainly for stock parts but who is using stock parts when they start milling and decking? Some I'm sure but not most. Besides, most of the time, taking .010 or even a little more won't affect things much at all if any and will sometimes make things fit better. After milling, mock it up before cutting the intake surface because once the cut is made, the metal is gone and you can't put it back without major surgery. Nothing in this world is perfect and Mom Mopar wasn't any different...

I completely agree. Cutting .010" off a head is a non issue, or at least I've never had any issues with it. Another thing is we all seem to swap from steel shim to composition head gaskets (or at least I have), which is a difference of ~.015" right there, and never give it a second thought. I suppose when you are cutting threads in your intake bolt holes with the bolts it's time to do something :idea1: