alex722607

iTrader: (4)

Hello all. I've been dormant for a while. My car is -on paper- a 1999 Pontiac Firebird with a 3.8. In reality it's a firebird that has had the LS treatment. The motor is a 5.3 which I put together several years ago and I'm starting to get a little bored with it. It has stock heads and a 00 LS1 cam, mail order tune.

I was getting around to getting a tune and I decided to do some upgrades before I dyno her. First up is the heads. I'm getting a set of 241's for cheap. I know the flow is better but compression will suffer. First question is what do they have to milled to?

I want to do springs and pushrods so I know I'm going to need atleast .650 springs with the cam I want and 7.4 pushrods. The cam I want is a torquer V2.
The car is an auto and has an LS1 intake, 3.08 gears. Any suggestions/ tips?

How much do I have to have the 241's milled?

wannafbody

iTrader: (2)

What heads on currently on the 5.3?

alex722607

iTrader: (4)

Stock 706's I believe, but I'll double check.

Mercier

iTrader: (15)

Food for thought: the major difference in flow is the smaller intake valve in the early truck heads. A machine shop can put the 2" LS1 intake valve in just by enlarging the existing seat. Then you have the smaller chambers to start with. Mill a little on those and get even higher compression than the 241s milled. Just another option for you as even with small chambers the early 5.3s were down on compression.