Anyone out there gotta torque curve for a stock 87 Z 305 TPI 5 speed? Always hear about the great low and mid-range torque, but never see Chevy's specs.

 

erm don't have a graph but if its tpi it peaks around mid to high 3k range and drops off

 

Chevy doesn't publish "specs" for such things. The best you'll get is what they "rated" the car at, which isn't necessarily an accurate reflection of what it does.

If you want to know what you've got, take it to a shop with a chassis dyno, and run it.

TPI doesn't produce "low end" as such any better than any other system. What it does do, however, is to produce an exaggerated torque peak across a rather narrow RPM range, due to the acoustic tuning effect of the runner length. That's why they called it "Tuned" port injection. They chose the particular RPM range for the peak in order to enhance the perceived feeling of power in typical street type driving, while producing good gas mileage and of course low emissions.

I think you'll find that it has a torque peak at around 3600 RPM, and that the output basically craters after about 4500 RPM. Peak HP is usually at around 4200 RPM. Your car should do peaks of about 210-215 HP and 320-330 ft-lbs at the crank, which translate to about 165-170 HP and 250-260 ft-lbs at the wheels.