| | | quote | Originally posted by Dennis LaGrua:
If that is the larger Duke Throttle body it may need the Holly Intake manifold. From what we read that TB really wakes up the Duke engine and is a significant upgrade.
If you are asking $1000 or more for it; what a potential buyer may consider is the cost vs gain. Some of the later GM Duke 2.5L engines as on the S-10, Cutlass Ciera etc, already have larger throttle bodies and better intake manifolds. That option may enter into the upgrade decision.
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Yeah, this is the Holley "big bore" throttle body for the Fiero. It's really nice, and I flirted with the idea of buying it... but $1,000 is just a bit more than I'm willing to spend on it. My personal opinion, I think a more reasonable price for it (brand new), would be around $600 bucks. They were about $325 new, and while they're rare (now), they aren't particularly too sought after since it fits only a very niche set of years.
It has a... I forget, like 18% larger bore, a slightly larger fuel injector, and an adjustable fuel pressure regulator. The quality of course exceeds that of the stock Rochester TBI unit (though honestly, the quality of the OEM stock units were quite good). They also come with brand new sensors that have been tested individually with each of the units.
I bought a brand new one (like this) way back in 1998/1999... blew a whole paycheck on it when I was younger, haha. I installed it on a 1984 Fiero 2m4 SE and didn't notice any difference in performance at all. BUT... that's because as you say, it requires a larger intake manifold. Specifically, the Holley comes with a gasket that "steps down" and allows you to mount it to the factory intake manifold. The problem of course is that the opening for the TBI is only as large as the factory one... so the gasket compensates (you can see that here:
https://images.fiero.nl/use...0240804_173023.jpg).But, if you use the other gasket along with the Holley intake manifold, it does add significant power, really does wake it up. You can also take the factory intake manifold and send it off to a machine shop to have it bored out (easily) to match the bore of the Holley TBI unit, and you'll get almost the same horsepower increase. As a drop-in replacement for the stock TBI though, without doing anything else, it doesn't increase power at all.
I was talking with Aaron earlier, I wanted to buy it, but I can't bring myself to pay $1,000 for it, haha... I'm hoping he reconsiders. I already have one that I bought from Synderman when he upgraded to a Holley Sniper EFI system... but it's been used and needs to be rebuilt (throttle adjustment has been messed with, etc.). Getting a rebuild kit is hard to find.
Another application for these TBI units is in the 1981-82, and 84 Corvette and 1982-1983 Firebird and Camaro that came equipped with the Cross-Fire Injection system. Believe it or not, the 305 with the CFI system used the exact same TBI units as the Pontiac Fiero... it just used TWO of them in tandem. Pretty cool set-up actually...
