3100 Malibu heads milling recommended

[mali2k]

Hi guys, I want to know what is the best milling heads for my Malibu 00 3100 engine? I saw on all sites that the maximum is .020 but I want to know if .040 is better? Anybody milling to .040?

[geoffinbc]

It is never "better" to mill the heads. Don't touch them if you don't need to. There is only 2 reasons to mill a head. 1. Its not perfectly flat and needs to be corrected for a rebuild. 2. You want a slight compression increase.

If you after the second scenario then mill the heads and block 0.010/0.010 don't take 0.020 out of the head.

[mickaz]

and number 2 is quite useless you MIGHT get 5 HP from it. less likely since you might only get back the HP you lost from an engine this old. Instead 3500.

[mali2k]

Ok, I want to get compression. I want to combine it with a racing cam. That's the reason why I want to milling.

[bszopi]

Milling the heads and a high-lift racing cam will result in bent valves, or at a minimum, the valves making their own releifs into the pistons. There really isn't a whole lot of room to play with inside the chamber. And if you don't believe me, ask Superdave, as he knows from experience (and I don't think his heads were even milled).

[Superdave]

put in a set of pistons for a 3.1 Camaro if you want higher compression (about 12:1), milling the heads is a waste of time. Your other option is to have the pistons shaved .020" then run camaro 3.1 headgaskets, that'll get you up to around 10:1


Yes, i have dents in my pistons. That's my cam's fault though. lol

[SappySE107]

You have to be careful with block milling, as the piston will then be closer to the head and your head gasket needs to be thick enough for clearance.

[mfuller]

My last 2 sets of 3400 heads have been milled .020".
Like you, I was looking for the (slight) compression increase.
Knowing what I know now, you should only mill the heads enough to get a flat surface.

[3400-95-Modified]

Little late to join the party here, but what amount would have to be milled off a 3500 head to get the CR back up to 9.5 or 9.8:1 when used on a 3400 block?

Not my question but one someone asked me.

I though it would be too much to bother with... He plans to still use all stock parts everywhere else, he just wants the increased flow of the 3500 heads.