difference in milling the head

[german hospitality]

Ok, so i have searched around, and im still wondering. My shee has procircuit platinum pipes, pro flow air box plate with a K&N filter with outerwears sock. and jetting. My question is that i want to mill my head, but dont know how much. I heard people say .025 and .030. What would the compression / performance difference be?? I know you can't go over .030 because of the squish band. But what would be the pros or cons or .025 vs. .030 ?? I usually run premium with a mixture of turbo blue anyways, so access to fuel isnt an issue. Also I live in mid michigan and ride around west branch which I think is around 800ft in elevation. Thanks. Also what should i clean/wash the head with after i mill it?? thanks. What increase in compression should i see. I think they are around 120 right now, but what is the best way to do an accurate compression test??

[bandanshee]

I was trying to decide on this same thing about a year ago, when I had my motor apart for a rebuild. I ended up going with .030, and have had no problems at all running 92 octane fuel. The main reason I opted for 30 instead of 25 was that my cylinders are ported and with the raised exaust port, naturally have less compression. This was one of the best mods I did.

my brother also has a .030 milled head, on stock cylinders with fatties, and he absolutely wastes my friend's shee that has a stock head and toomey t6's, and the t6's are supposed to make more power than the fatties do (?)...

As far as compression goes, I don't know exactly, but id say both 25 and 30 would put you in the 155-165 range at your elevation. Id go with 30.

[german hospitality]

Thanks man. Is there a ratio that says you gain so many hp's when you gain so many psi? If so is it common accros the board is the hp gain in each cylinder? Also is the a psi difference between the .025 and the .030. I mean is there like 3 psi per .005 taken off or something? And what is the boarder for premium to mixing 50/50. Is it like 160psi or so? thanks.

[rocketboy]

.025 isnt shit ...yo u can mil l.035 off with no problem for clearance . it iwl l be roughly 20.5cc domes when its done and should raise compression about 25-30 lbs in each cylinder a good mod worth doing .