Carb gurus?
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Joined: Jan 2000
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Carb gurus?
If any of you have played with holleys a bit and know a thing or two I'd appreciate some help. I'm due to get my 390 back from the shop any day and need to get the carb dialed in before I fire it up. Here's the background: 390 w/Edelbrock aluminum heads, performer RPM intake, .525in lift, 224 degree cam, 9.5:1 compression. I run a '76 F250 (roughly 5500lbs) with 4.10's and 38in. Swampers, and a 4 speed. I just took the engine in for rebuild, it was in the truck before. Problem is, the 750 double pumper on it never allowed it to run just right. I tried different jets and power valves but it always had a big bog under 2300rpm. It also ran a little rich but that's OK, I just didn't jet it down that much, I settled on 73's and 80's. If you all could give me a good baseline jet and power valve setup I'd appreciate it.
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Joined: Jun 1999
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Carb gurus?
In my opinion, you should go to a vacuum secondary carb,and leave the double pumper for an all out mud racing weekend kinda thing. It is very hard to dial in a double pumper unless you have asome hard core info from a dyno test for a set up just like yours.Just to give you an idea on how carb tuning is delicate , pick up the latest issue of Car Craft (April) and there is an article(based on a chevy) on dialing in a carb to a stock exhaust,and then after adding headers and duals, having to re-dial the carb in . Very interesting the way the jet sizes changed in order to produce peak levels.
Phillip
Phillip
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