Milling 225 head

With the original head gasket (.021"), you need to mill around .060" off. But those are getting hard to find. With a later head gasket, like .050" thick, you need to take around .090" off. Suppopsedly, you can got .100" off. But I've never done that much, so I suggest you read the articles at www.slantsix.org, and check the forums there.

As above, the rockers need to take up the adjustment for the head being lower on the pushrods. That should not be any issue. Cam is in the block so the head milling does not effect the cam timing.