Well I am pretty happy with my flow numbers so far on my L98 cast heads. After 35 hours of grinding and installing 2.02" intake valves the first one went on the superflow 600 bench today.
It became turbulant after .500 lift but peaked at .500" at 245cfm. They flowed within 5cfm of an AFR 180 through .100" to .500" I have not had the valve job done on the exhaust yet so it was not flowed. I had a friend, who ports heads, help me and finish out the ports. He still thinks we can get at least 10 cfm more out of them with chamber work.

 

That's impressive.

Any chances of pic's?

I think I'll request a HeadPorting Forum to keep these all in one area.

 

Agreed. that would be a nice idea.


BTW Great #'s

 

Thanks,
I will post pics when I get them finished, along with exhaust/finished intake numbers.
Charlie

 

I couldn't help but notice your impressive et's out of a stock motor.

Apparently, steeper gears can help out the tpi to some degree.

I can't wait to see your times with the heads back on, low 13's on a TPI motor with no aftermarket parts, ha ha.

Keep it coming, I'm interested in seeing your pics.

 

Thanks,
Low 13s is the goal. I am also porting the upper, siamese porting the lower plenum, LT1 cam, adding a cutout and long tube headers. The 3.73 gears picked up about 4 tenths and helped my 60ft come down from a 1.97 to a best of 1.81. I just want to surprise some LS1s
Later,
Charlie

 

Which gear ratio did you swap from? My brother drives an '88 GTA and its equipped with the 2.73, or 2.77 or whatever rear-end. Even with the long-legged gears, that thing pulls out of the hole like a freight train compared to my carb'd 350. I'm actually trying to sell off the 'ol firebird now, I just can't stand the daily driving during our winters with a carb, plus it just doesn't have that low-end nut of the TPI. I figure I'd get more out of picking up my bro's GTA for peanuts and with some simple mods, I'll be a whole lot quicker with better fuel economy and without the hassle of waiting for the pig to warm up. =) I love the 3rd gens though, definitely one of the best bang for buck platforms out there right now.

BTW: Why are you swapping to an LT1 cam? Isn't the profile of that cam, similar if not tamer than the L98 cam? I could be wrong, I just can't be bothered to look. If you're going with headers, and have free-breathing heads, step 'er up a notch man! Unless you have ****-retentive smog laws...

 

Update:

Finished heads
Intake peaked @ .480 lift flowing 248cfm (+50cfm improvement from stock)
Exhaust w/EGR port unfilled peaked @.500 flowing 181cfm (+60 improvement from stock)
This was a lot of work, but I am very pleased with the results and can't wait to get them on the car.

Later,
Charlie