djm_e22

iTrader: (2)

I posted this in the forced induction section. Hoping to get a little more replys here. Just wondering for all of you that boosted your stock or ported LT1 heads. What amount of boost were you able to give them and if you know what rwhp you got? Could you give what transmission and rear end you had? Thanks.

Lonnies Performance

iTrader: (16)

650 (approx 220/230 cam, 15# boost, 9.25 comp) to 750 rwhp (approx 236/248 cam, 18# boost, 9.25 comp) is entirely possible with stock ported heads. Done a few of these (383 cube) through both M6 and 4L60E transmissions. Once you start to surpass this level, there can be enough deflection in the stock heads, due to limited deck thickness to cause some gasket or chamber cracking issues.

There have been a few ported LT4 headed cars to get near the 1000rwhp mark, but longevity is not to be expected.

If you plan to push it hard, start with a strong head so you do not break parts & have to start over. Personally, I would say anything under 15# boost should be OK with the proper tune.

blk6speed

639hp/641tq at 14#,355 self ported stock heads and intake..

Evaporate

iTrader: (22)

Good info Lonnie.

blk6speed, what size cam do you run? Which blower? Man, I really hope I can get close to what you guys are showing with my T-trim.

To the OP, are you keeping the same NA setup when you go to boost? Looks like you make good numbers on that combination.

djm_e22

iTrader: (2)

I will be pulling my engine to get some low compression pistons because right now I am at about 11:1. Plus I will need to change my cam because the 306 probably isn't the best turbo cam. I will use my stock heads till it looks like I hit 15lbs of boost, according to Lonnie and several people. After that I will switch to some Trickflow heads. I'd like to have some room to grow that doesn't require me pulling my engine again, I won't mind changing heads. But before I do all this I still have yet to use my nitrous with my currect setup. I am a little nervous but I have all the safety features. So we will see what happens with that.

69gto96z

iTrader: (13)

Nice numbers, almost identical to what I want to build here in the near future. What size turbo are you running? I'm guessing it's turbo from your avatar.

slomarao

iTrader: (6)

With an FI app head flow can lack because of the air being forced into the motor. Make sure to have the exhaust ports done very well, getting the air our is important.

A LE2 flowing head with extra exhaust work done should support 650-750rwhp.

blk6speed

its been a long time and i lost the cam card ..the cam is a custom grind from comp cams,i told them that i was going to run the stock heads/intake and they ground it to match..the turbo is a rear mounted precision gt42-76