390 Carb problem questions
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Junior User
Joined: Apr 2004
Posts: 72
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390 Carb problem questions
I have a 390 with and edelbrock performer rpm intake, performer rpm cam, and edelbrock heads. I also am running dual exhaust through headman headers. My carb is a Street avenger 770. My engine runs terrible when cold. Its so bad that its hard to keep the engine running for the first couple minutes and forget about trying to drive it without completely warming up. Ive adjusted the choke every way possible and all the electrical connections to it are good. The engine runs good when warm but not great. Is this carb just too big for my setup? Ive been thinking about going to an edelbrock 650. I had an edelbrock on it before I did the cam and heads and I liked it better. Truck ran great no matter how cold it was outside.
Lead Driver
Joined: Oct 2004
Posts: 8,062
Likes: 35
From: Central Oregon
When I did the build on my 460 in my Bronco, I was looking into Edelbrock heads and intake, but when I spoke to my engine builder, he did not reccomend it here in Oregon. I use the truck alot in the winter and the aluminum would stay cold and make it hard to warm up the engine. I don't know how cold it gets where you are, just something that may cause a problem.
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Post Fiend
Joined: Dec 2003
Posts: 6,658
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From: "Islander"
I run a 670 SA (plenty big) on a 414 with aluminum intake, set the electric choke then start. Idle is 650, bump throttle to 600 in 20 seconds, bump to 550 in 20 seconds and drive off under light load of 800 rpm's. After 3 minutes driving motor runs normal. This is in S.F. bay area with mild temps, 40-50 degrees in the morning.
I'm a firm believer of a exhaust heat crossovers in the intake for these cold start daily driven trucks for which is eliminated with many aftermarket intakes.
The Old Edelbrock F427 (35 years old) has heat crossover.
Just because they sell it doesn't make it right for your application just your money in their pocket.JMO's.
I'm a firm believer of a exhaust heat crossovers in the intake for these cold start daily driven trucks for which is eliminated with many aftermarket intakes.
The Old Edelbrock F427 (35 years old) has heat crossover.
Just because they sell it doesn't make it right for your application just your money in their pocket.JMO's.
Senior User
Joined: Nov 2005
Posts: 176
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The edelbrock aluminum heads and the edelbrock performer rpm have no provisions for the exhaust crossover passage. This is need for cold weather so that the fuel stays atomized within the passages of the intake manifold. It may seem fine when the engine is completely warm, but your fuel mileage may suffer. For a truck, I would have stayed with stock iron heads that have been worked over with some better components, edelbrock performer 390 intake. Going with the smaller carb may be a wise choice as well.
