355 Vortec w/ X268 need more power

[chiphead]

Hey, new guy here...

Changing stall, tranny, gear ratio, etc may make the car faster at the track, but doesn't actually increase engine output. NOS is nice, but if you're running hyperuetic (sp?) pistons you've got to be extra careful so the NOS doesn't get out of the safe operating area.

For a street car thats got to run pump gas, I'd keep the static CR at or below 10:1 with iron heads. Stick with a dual-plane intake if you're thinking of swapping to numerially lower than 3.73 gears. Single planes are great, but you've got to increase compression or wind it up to get around the low-end torque issues. I think you realize this cuz you're mentioning the intake runner sizes for the heads you're looking at. Perhaps some high-ratio roller rockers, or fast-bleed lifters if your combo will tolerate it. Some gasket matching, bowl blending, swirl polish valves would improve power and help keep some low end torque using smallish intake runners and decent compression. Its all about keeping up the intake port velocity.

The OD tranny would be cool on the street, but may take more cash to make it survive at the track. Stall speeds mentioned might be a little high for a nonlockup converter on the street. The TH350 takes less power to run than the TH400 and the OD (I think), so you can keep from losing some power there.

Of course silly stuff like spark curve, carb tuning, underdrive pullyes, etc can improve the respose of an otherwise well thought out combo.

Hope this helps, and its worth everything you paid for it....

robert

[96capriceMGR]

His power numbers will not be too crazy an OD tranny can be made to handle it, just think of the power the last of the Camaros had and what the Vette(a transaxle but still 700R4 based) makes. There are guys running 10s with full weight 94-96 Impalas with 4L60Es(electronic 700R4), I even know a guy who on juice put 466hp 611ft.lbs. to the tires stock/original tranny(and shortblock for that matter) not even a shift kit. Not to say OD trannies are completely trouble free, but when put together right they can work well in a performance application, and the lockup converters are great.

[SMOKEmUP]

[doug242ti]

Dont forget the GN guys