Minimum Cylinder Head Surface Area?

[mmdoctor]

Guys,

Have obtained a used set of Mopar Aluminum Magnum heads (#P4876624) and looks like I might need to have the surfaced milled. Don't know much history on the heads, but it looks like they've been worked by someone before?

Been trying to find what the minimum surface material measurement is for these heads to see if i can even have them re-surfaced one more time and am striking out. Tried calling the local dealer, Mopar Performance, a couple local machine shops, all to no avail. I called Edelbrock and they told me 60-thou is the minimum they use on their aluminum heads? This sound about right?

Heads are going on a full roller 1996 5.9l magnum block in a weekend driver only, pump gas.

Thanks in advance for your help!

 

[moper]

The hard part might be trying to find an un-modified set to get a base measurement for but you can always use the measured chamber volume if the chamer itself wasn't changed much and use that figure vs published specs to get an idea of how far they went. But - most good race shops will have the correct transducer for aluminum and a sonic test will tell you how thick they are. If you're only talking about a clean up cut for gasket sealing ability (like surfacing for an MLS type) then it'smore than likely just fine. Those cuts don't remove much at all.