So i was looking into 5.3s for some time, and just came into the info that my school has the tools and shyt to mill heads.. this would be free minus cost of head gasket and time to remove/ install heads

i figure .030 off will put my a lil higher CR han 5.3s

would i need a tune for this?
how much HP would i gain?
will valve clearance be an issue?
93 gas good?

more questions to be posted...

Alot of it will depend on your motor and mods. Milling .030 would put a stock ls1 head around 62cc, which is the same as a stock 5.3 head without milling. Assuming stock ls1 bore and head gaskets you would be around 10.8:1. Maybe a 10hp gain. Valve clearance will be an issue depending on what cam you are running. It will definatly limit the range of cams available without flycutting the pistons. Using good 93 octane should be ok and you shouldn't need a tune. Don't forget you need to buy new head bolts too.

i would get a tune so no hp is thrown away.

I can't imagine spending $400 to pick up a couple of horsepower. Your talking a 10-15 hp gain by milling the heads, and compression shouldn't change your air/fuel ratio so there's not much a tune would do to make more power. If anything you might need to pull a little timing if detonation was a problem with the higher compression, but that wouldn't get you anymore power.

$400 for 15hp is more cost effective than most bolt ons, but im thinking its more of a hassle than its worth