What is a safe amount to mill a slant 6 head? Will there be pushrod issues?

You can safely mill .090 off if your slant is stock...(there maybe more in there since factory tolerances weren't so good...I milled a 1963 head a lot just to get to 'stock' compression...)

The best way to go about it, is get/borrow from a buddy a caliper, when you remove the head...run a piston up to TDC and check the depth (most are like .145-ish)...

Someone on here can run a comp calc for you or direct you to an online calculator so you know how much to really mill and not get too much off
(some have plugged .100 off and got to 9.5: compression and run super...)

-D.Idiot

p.s. while in there, you'll need to check how flat the deck is, and you might check your valve seat and guides for wear too...

pushrod issues will depend on how much you munch off. if you just decking (skimming or assuring true) you probably will be okay, but since you asked for a "safe" amount, I am guessing you want to know of more of a maximum amount. I belive .090 will need new rods, but again, you just need to measure.

.090 seems to be a general max, but I have heard of .110. it really does depend on the individual head just as dusteridiot said. the tolerances were all over the place back then.

is something warped or rusty on your head? is that why you are looking for a maximum or are you looking for performance?

I have also heard of people "slant" milling .200 off of the head, whereas you take nothing from one edge and by the time the tool reaches the other you've taken .200.

someone on here has done it but I can't remember who..............sorry.

I took of .100, no pinging. The angle of the rockers looked a bit strange, but that was much better when I got the regrinded cam.

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Lasse

Signet -66 225
Holley 600 Offy-5270 Dutra Dual,regrind. cam 272 0,420 110, head shaved 0.100 slight.ported
MSD6A
A904
7 1/4 3.23

When I had mine done, I had the mahine shop take .060 off of the head and .020 off of the block. After it was done and measured, I took the head back and had them take another .040 off the head. .030 over with Comp 264 cam and stock pushrods.
Chambers came in around 46cc, pistons are down .165 and the .032 gasket brings it to 9.2

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225 .030
.020 off the block .100 from head
Comp 264
904 Tranny
New Ebre-ting

http://s78.photobucket.com/albums/j103/edrod01/

I would say you can safely Mill a head to .110" that 's What I did on mine - If you leave the block alone and if you do not change the cam You will need shorter pushrods.
If you use a higher lift cam you can get away with the .110' head shave due to the smaller base circile the cam lobes provide.
Anytime you mill the head or block, Check the pistion to Valve clearence to be sure.

I ran a combination with .110" off the head, .100" of the Block and .528 Lift at valve with no clearance issues - Of course I checked it to be sure!!


Greg

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http://www.youtube.com/hyperpack

I know people who have taken -.125" off the head with no problems.

Pushrod length will depend on cam base circle, milling, and valve stem length. You may need new ones, you may not.

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Official Cookie and Mater Tormentor.

You can buy spacers to raise the rocker arm shaft instead of getting new pushrods. I did this on my 360, and it worked fine.

Sam

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Thanks for the great response! I am planning to use the head off my retired 68' Val. It was was gone through a couple thousand miles ago ( valves ground, new seals and guides). I am contemplating doing a conservative port and polish besides the shave. I plan on running the stock cam for the time being. This forum rules!

>You can buy spacers to raise the rocker arm shaft instead of getting new pushrods.<

Sam,

Where would I purchase these?

Would this work with the hydrauling lifter setup?

TIA

--Walt Jackson