SBC 383 missing a lot of power
08-02-2009, 05:41 PM
#13
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Join Date: Aug 2009
Location: Shipshewana
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Re: SBC 383 missing a lot of power
Originally Posted by lmccoll
We have a new 383, 12.5:1 compression, Brodix racerite heads ( flow about 270 CFM at 0.6 lift) , a solid roller cam with 0.6 lift, 292 total duration, Victor Jr intake and a Holley 750 double pumper. Headers are some used ones I had that are 1 5/8" tubes. Open exhaust. Ignition is a MSD distributor with a high RPM module, all new plug wires etc.
Total timing is set at 35 degrees at about 3500 RPM and up. We run 110 race gas.
Based on our ET's, I am only making about 410 horsepower. The engine was professionally built by someone that has built race engines for about 20 years. They said it should make near 550 HP. The only info they didn't have was the size of the headers.
I have rechecked the timing and it is still at 35 degrees. Going down the track, it pops in the exhaust some, indicating it is running really lean. I don't have a air/fuel monitor to check it. Fuel pressure at idle or reveving up the engine is about 6 lbs.
One thing I don't know is if the fuel pressure is holding going down the track. I have 1/2" tubing all the way from a fuel cell. The tank is vented ok. The fuel pump is new, it is a JEGS 130 GPH pump.
Any ideas would be greatly appreciated.
The only thing I can think of is the fuel pump is not pumping as much as it should.
Total timing is set at 35 degrees at about 3500 RPM and up. We run 110 race gas.
Based on our ET's, I am only making about 410 horsepower. The engine was professionally built by someone that has built race engines for about 20 years. They said it should make near 550 HP. The only info they didn't have was the size of the headers.
I have rechecked the timing and it is still at 35 degrees. Going down the track, it pops in the exhaust some, indicating it is running really lean. I don't have a air/fuel monitor to check it. Fuel pressure at idle or reveving up the engine is about 6 lbs.
One thing I don't know is if the fuel pressure is holding going down the track. I have 1/2" tubing all the way from a fuel cell. The tank is vented ok. The fuel pump is new, it is a JEGS 130 GPH pump.
Any ideas would be greatly appreciated.
The only thing I can think of is the fuel pump is not pumping as much as it should.
