Milling 360 J Heads

[jakuzzie]

I am thinking about milling my 915/587 heads to increase compression on my 318. Has anyone done that? How much can be removed and how much should be removed from the intake? 1.88 valves and KB167 pistons are used.

Thanks.

 

[Syleng1]

My machine shop took .020” off a set of 318 heads for me.
No issues.

 

[66fs]

.040 will get you to 64.7cc, then mill the intake side of the heads .038 to put them right.

 

[RustyRatRod]

Those pistons are 2 valve relief flat tops with more than 1.8" of compression height. I'd be careful milling the heads as you could end up with too much compression for pump gas. I'd figure compression with what you have first.

 

[SSG_Karg]

I did exactly that a few years ago. I milled .050” off the deck surface and .040” off the intake side. It reduced the chamber from 67cc to 57cc. They had 2.02”/1.60” stainless valves installed and it raised my compression ratio a full point. I was still running stock replacement pistons that were about a mile down in the hole so I went from about 7.5-1 to 8.5-1. Lol! If I ever put a set of good pistons in it at zero deck it should be pretty sweet.

 

[mygasser]

i have 2.02 j heads for my 318. instead of milling the heads i've got a set of kb399 domed pistons. it's another option for you.
neil.

 

[Cranky]

It's best to check the intake before milling for fit. Years back I found that production tolerances could be be pretty wild....at least it was on the big blocks. Why would it be any different on the SB's? Also, I like to mill the head for intake fit instead of the intake. That way the intake will still be useable on other unmilled engine/heads.

 

[jakuzzie]

Thanks for the feedback.

Those heads are used and require machining anyway and I am just figuring out the compression I want to go with. Still want to use 95ROZ.

The KB167(+0.60) are already installed and my crankshaft is balanced on those.
Pic is from Hughes. How accurate are those compression ratios in relation of cc?

 

[MOPAROFFICIAL]

9.6 would be about idiot proof.
Good luck!