300 GPX Mule article

**Anthony Smith** · 10-10-2012

300hp intercooled L67 straight from the GM engineers. I wonder why the production motors always managed to lose the factory intercoolers all the concept cars seemed to have.
1995 Pontiac 300 GPX - Supercharged V-6 Engine - High Performance Pontiac Magazine

**MoarkatsINmuhtrailer** · 10-10-2012

Because the cars would have whooped on fbodies and vettes at the time.

**blueguy** · 10-10-2012

Yup.

can't have a family sedan pooping on a flagship sports car.

**rperry435** · 10-10-2012

I agree totally

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**Tuner-Extraordinaire** · 10-10-2012

I disagree.

GM didn't want it's lunch eaten by 25k cars that could beat the 40k flagship car.

**dsmuts** · 10-10-2012

Originally Posted by blueguy91

Yup.

can't have a family sedan pooping on a flagship sports car.

What about the sho's vs. foxbodies?

**Tuner-Extraordinaire** · 10-10-2012

Originally Posted by dsmuts

What about the sho's vs. foxbodies?

Apples and Oranges is just like GM and Ford.

**blueguy** · 10-11-2012

Originally Posted by dsmuts

What about the sho's vs. foxbodies?

Because the fox was on it's way out within the next year or two.

GM had JUST released the C5 as the replacement in '96 when the 300GPX hit the magazines.

**TLSheff** · 10-11-2012

Yup both versions of the cars were faster than the Corvettes against it.

95 out-performed the C4 LT1 car
96 out-performed the C5 LS1 replacement

Funny how they just removed the intercooler, put a bigger pulley on it and retuned and that is what we have now. But the Thunderbirds never lost the inter-cooler option. I know it was alot smaller intercooler but still. Ford didn't lose any hits on Mustangs due to the thunderbirds, but GM was scared of the L67 power against its LSx motors.

**TLSheff** · 10-11-2012

BTW anyone know what "series" M90 this is? Its not the same as out Gen3's... just looking at it you can see its different.

**Bio248** · 10-11-2012

doesnt look like an m90.

**TLSheff** · 10-11-2012

But... it is... at least according to the article above.

With such a solid foundation for a performance powerplant, it seemed natural to put a supercharger on this engine and take the performance to another level. The supercharger in question was not the Eaton Model 62 used on the 3800 Series I, but the larger Model 90 that displaced 90 ci per revolution.

The larger blower allowed the maximum 8 pounds of boost to be generated at a lower overdrive ratio, which reduced blower speed and charge air heating. It was mounted on an experimental intake manifold that featured an integral liquid-to-air intercooler. The intercooler had its own separate cooling core and pump and used a mild glycol solution for heat transfer. Its throttle body was fed through a special ram-air system that inhaled cool outside air, further reducing charge-air temperatures.

To complement the forced-induction system, the exhaust system was also upgraded from the factory cast-iron manifolds. A pair of one-off headers were fabricated by SVE with 1.75-inch primaries, a 3-inch collector/crossover and a 3-inch catalytic converter. From there a dual-outlet exhaust system featuring 2-inch pipes routed spent gases out.

**dsmuts** · 10-11-2012

Originally Posted by blueguy91

Because the fox was on it's way out within the next year or two.

GM had JUST released the C5 as the replacement in '96 when the 300GPX hit the magazines.

And the fox got replaced with an even slower car lol so the sho's were even faster than the 94+ lol I think the first year of the sho was 89ish so they had a 5 year overlap.