Aftermarket Horsepower

[73stinger]

Which aftermarket bolt-on increase horsepower the most?

[Stallion]

I think you should bolt on...a ZZ4.

[Flared69]

depends what your engine has.

Probably extractors/headers, carb and a performance intake manifold.

[Flared69]

or a supercharger.

you generally need to put a different cam on and put it on an already performance engine though.

[Stallion]

Just make the engine breathe. Exaust, intake, if you want fuel injection that's a good one. It all depends on how much you want to spend. Then if you have the engine like Flared said, you can put on a supercharger and then NOS if you want some juice in her.

[80convertible]

I had my car on the dyno after installing vortec heads. The owner of the shop was tuning my carb for me on the dyno. He noticed that my mechanical fan clutch was not releasing (was a new fan clutch with less than 1,000 miles on it), so he asked if he could dyno my car with and without the fan/clutch. The difference was 15hp and 12ft-lbs of torque. Needless to say I installed a 16" electric fan the next week for less than $120.00. I don't believe you can get 15hp for less than $120.00 doing anything else. Also makes the engine bay cleaner and safer.

[Jacko]

Originally Posted by 73stinger

Which aftermarket bolt-on increase horsepower the most?

You say "THE MOST"???
What do you mean by the "MOST"?
Cylinder Heads !!! will make a world of power....but they need to be matched to be effective. Cam, intake, exhaust, etc.
A blower makes tremendous power, but that is a different league than what I am guessing you are after.
But a blower (such as a GMC-8-71) is just about the ultimate power producer.
That is cubic dollars and not street friendly.
And to run one on the street, you had better understand motors completely.

[Stallion]

Originally Posted by 80convertible

I had my car on the dyno after installing vortec heads. The owner of the shop was tuning my carb for me on the dyno. He noticed that my mechanical fan clutch was not releasing (was a new fan clutch with less than 1,000 miles on it), so he asked if he could dyno my car with and without the fan/clutch. The difference was 15hp and 12ft-lbs of torque. Needless to say I installed a 16" electric fan the next week for less than $120.00. I don't believe you can get 15hp for less than $120.00 doing anything else. Also makes the engine bay cleaner and safer.

How does that work, though? Where do you connect the fan to? Where does it get it's power? Is there any fab needed in that?

[Stallion]

Originally Posted by Jacko

You say "THE MOST"???
...
And to run one on the street, you had better understand motors completely.

What do you mean?

[80convertible]

Originally Posted by Stallion

How does that work, though? Where do you connect the fan to? Where does it get it's power? Is there any fab needed in that?

Actually, this project was very easy. I fabricated a mount for the fan with 3 pieces of aluminum from Home Depot using the factory fan shroud mounting locations. I simply created 3 sides of a square, mounted the square to the factory shroud locations and mounted the single 16" electric fan to the 3/4 square using stainless steel bolts. I found an unused 12v wire in the engine compartment to supply power to the Painless Wiring electric fan wiring harness. You could also run directly from your fuse block. This harness includes a relay and 30 amp circuit breaker and fan temp sensor. The temp sensor installed directly into the intake manifold. I would never, ever run a mechanical fan and clutch again. Email me if you want more details.

[Stallion]

Hey, that sounds like a good job, 80convertible! Beneficial too, I assume.