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Road Demon 625

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Old 06-28-2009, 10:28 AM   #1
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Join Date: Jun 2009
Location: Where Ever I May Roam
Posts: 85
Car: 1989 Firebird Formula
Engine: 305 Road Demon 525
Transmission: 700 R4

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Road Demon 625

So long ago I ditched my TPI because it kept throwing error 32 or something and the car was never happy with whatever sensors I gave it. The car never really ran right with that tpi setup. My brother gave me some holly.. 600 something maybe.. it was like a Frankenstein carb made of several other carbs lol even had some jb weld in place of some screws. After several years it finally died and started pissing gas straight up and straight back down into the barrel lol That was quite the funny sight. I didnt care for that carb so.. NEXT!

Here is where the fun starts. I bought a Demon 625 not knowing if it was right for my 305. I guess I could have done the math on cam and heads but.. screw it didnt think to get that technical. I poped it on and had a hell of a time tuning it because some jag at the speed shop sold me a fuel pump that he said put out 8 to 15 psi. I cranked down the fuel pressure on it as low as possible and put TWO! regulators on it for the hell of it and it was still putting out 15 psi. At that point... I knew the idiot sold me a part that the computer or book told him belongs to my car, a fuel injected system it would say.

Its been 2 years since I bought it so I cant return it. I went to pep boys and bought some cheap plastic micro something or another electric fuel pump that puts out 8psi. Wired it up, ran it straight to the carb and with a repair list from hell, some timing and tuning adjustments she was purring like never before. This Demon makes quite the nice idle sound from my exhaust and gets LOUD when I romp on it.

So I shut the hood at midnight and poped off the ttops to go for a test drive. Found some old warehouses with no a single living soul to its name. Dropped down to 1st gear and gave it a real test. I swear to you... this car has NEVER Ran better than this! Even for a 305 it had a nice pull to it and of course the ws6 suspension was tight around the corners. No need for high end horse when I'm just doing cornering. The tires now break loose easily and the throttle response is Amazing! Its so crisp lol.

All in all the Road Demon 625 seems to be a fit for this 305. I have more room to test as my A/F ratio gauge started readnig a bit rich after the test drive but not by much. I'll do the math later on a 625 and see if its still a bit much on this 305, maybe then I can put that thought away that sits in the back of my head. I'll post what I find here. If it is to much, ehh.. wouldnt hurt to slip in a bigger cam to eat up the gas but lol no way am I getting rid of this carb. I've become a huge fan of Barry Grant now and I never want to run without a Demon under the hood again!
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