SLP has christmas specials going on now.....249.95 for there runner kit. Not to bad IMO compaired to there usual $400.00. My question is i have a 89 formula TPI with the 305. Nothing major to the engine. Ram air kit, air foil, K&N filter a a few little other things. My brother has a 90 vette. Again...nothing major to the motor. Is it worth putting these runners on? Me and him both have to dismantle our plenums over the winter cause were changing our fuel injectors out, so then would be the time to do something. SLP states "20 extra horsepower". Were does the horse come in? Which RPM. Do you lose any torque or gain any at all? Any help would be great. Thanks guys!

 

On the vette add the runners, on your firebird since it is a 305 with the peanut cam. It will probably make no difference and may even slow the car down.

 

so there is a significant difference with the cam in my formula VS my bros 90 vette?

 

Yes,

Your 305 TPI auto car has the following cam spec's:

Duration @50"
Intake Exhaust
179 / 194

Valve lift
Intake Exhaust
.350" .384"

The TPI cam in the Vette, 350 IROC, and 305 TPI 5-speed cars.

Duration @50"
Intake Exhaust
202 / 207

Valve lift
Intake Exhaust
.404" .415"

As you can see the 350 TPI and 305 TPI 5-speed cars have a much more aggresive cam shaft. Usually, at least a solid 25 - 30 hp horsepower difference and it drasctically changes the power band of the motor.

The TPI auto cam can only rev to 5000, compared to 5500 on the 350 and 305 5-speed cars.

The SLP runners will move to much power on your motor to a higher rpm range and probably hurt your performance. Since your cam does not make any power in the higher rpm range.