I'm currently working on a Ls head. The question I'm wanting to ask is, what amount can I mill off before I start getting in trouble. I don't have the money for pistons so don't suggest it. I'm not going to put a v-tec head on either so don't suggest that either. I just wan't to know about the milling.
This is what I currently have. B20b block with Ls head and crower 62404's. I've got a spare head that I'm porting and polishing and before I stick it on the car I wan't to do everything possible to squeeze as much juice out of it as possible while still being safe.
Let me know what you guy's think.

 

of course clearance has the final say on what mill you can safely run, but i'd say with the non vtec head you could get away with around .035" that'll get you a bit of compression, but it'll mess with your timing also so be prepared to correct it or go with a little les mill, like around .020"

 

If your running a stock b20b block (stock pistons) you're going to need much more compression to effectively run Crower 404's. Then of course you're going to end up with less valve clearance. To be safe, clay your motor.

 

I just recently dropped a head with 404s in, milled .018"

Which should retard the cam timming by 1.5 degrees

at 3.5 degrees retard on the exhaust cam, there was clearance issues.

At 9.5:1 CR, you will at least retain the stock cranking pressure with the crower 404s. You of cource will make more power in the 25% increase range (which is around 11.5:1), but its better than loosing cranking pressure.