I was looking at a Helix Power Tower spacer plate designed for trucks with TBI. However, it seems like they make one that would fit my '91 305 TBI. The company preaches both an increase in horsepower(20HP) and a reduction in fuel consumption(6MPG). Does it work as well as they say? For eighty bucks Canadian, it really seems like a good deal.

 

Don't believe it. Those pieces are so overpriced and the "swirl" is bad for hp, good for gas milage. You can't have both unless you have displacement and good gearing. You want more power....you need more gas to keep the air fuel ratio around 14.5 if you want gasmilage, you want to run with a more efficient engine for your aplication (not HUGE displacment).
The spacers are good really for one thing, isolating the heat from the engine. It works better in carbs but everybit helps. I would just get a gasket from a local parts store and bring it over to a machine shop and tell them to make it out of aluminum or some heat resistant plastic (microwavable ) They shouldn't charge much if it's plastic. Infact, if you do it with plastic, get a cutting board from some mall store and do it yourself. Get a 1 11/16" drill bit and start cutting .
You won't hear people talking about them because they usually do nothing as far as performance. Just ask around, better spent on gears, posi, cam swap, and those goodies.

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, Jon (350 TBI!)
91 Red My website

 

Thanks for the info, I'll steer clear. It's strange that it actually hurts HP because that was the primary advertising feature: that the Helix could increase horsepower and low end torque. The mileage part was mentioned more as an afterthought. Don't believe everything you read, I guess...