What's the bottleneck in my engine?

[ItBites]

I know, I know, I said I'd evaporate from this thread, but I guess I lied... Durn Chevy folks... I couldn't resist talkin to another Chevy Cobra guy... I been so lonely...


Bevan,

I think an LS-7 should have had rectangular port heads(?). If they are ovals, you are past their usefulness at 7000 RPM, but apparently it runs pretty good. I've had my Cobra past 170 mph (Radared at Brainerd Int Speedway) and it still had quite a lot in it, but 190 - wtf dude?

I use Chevy W-port aluminum heads that are flowed BIG time. My cam is something like .690 lift and 270 deg at .050. I never had it on an engine Dyno, but RWHP was 505 at 6000 RPM when the tires smoked on the roller. I shift at 7400 and the slope of the HP curve was still pretty steep. I also have injection and that is good for a few HP since manifold density can be raised to near atmospheric density without losing proper mixture.

I'd guess about 625 for your combo with oval iron heads, but at 190, unless its really light, its better than that, so either I'm conservative or your heads are better than I could imagine for oval ports. With rectangular heads flowed etc, I'd guess 700 at 6800 RPM.

BTW, you're right about much of the HP claiming going on. My car is so loud to get the HP I have that I've been kicked off several tracks across the country. I've never heard one louder or with as much pop/crackle as I get. 12.5:1 does that.

Anyhow, keep the dirty side down (at 190 - wow!!!)