Ive got a 1988 k5 blazer with a built 350 engine. Last summer I bought a holley 750 carb with vacuum secondaries and electric choke and i spent forever finally getting it tuned to where I thought it ran right. The truck started on the first or second crank everytime and it idled at around 900 rpm. It took off and drove perfectly never backfiring or choking. Untill I really got into it, if i floored the truck from a stop then at about 60 mph the engine would start sputtering because it was running out of fuel, if i took my foot off the gas for a few seconds the bowls would fill up and i could slam the gas back down, and i also feel like the truck could be making more power at all rpms.
The truck used to be tbi so it has an in tank factory style fuel pump that puts out about 15 psi that I have regulated to 6 psi. I don't know the exact specs of the cam but I do know it is on the wild side with a pretty rough "race car" sounding idle and the compression is a little higher than factory at 10.5:1. And the th400 trans has a 3800 stall converter in it, a bit high i know but fun when your getting into the throttle. And if it matters I have 4.56 axle ratios.
My question is whats the best way to fix this high speed/rpm sputtering. I also have a holley 670 street avenger with large jetting (90 something). Would the street avenger be a better choice for this engine because its supposed to be a performance carb. I was also thinking about a 650 or 750 double pumper but I don't know if that will be too much for this engine. Or am I looking at this all wrong and ignoring the fact that I might need a higher volume fuel pump?
Any help or suggestions would be great.
The truck used to be tbi so it has an in tank factory style fuel pump that puts out about 15 psi that I have regulated to 6 psi. I don't know the exact specs of the cam but I do know it is on the wild side with a pretty rough "race car" sounding idle and the compression is a little higher than factory at 10.5:1. And the th400 trans has a 3800 stall converter in it, a bit high i know but fun when your getting into the throttle. And if it matters I have 4.56 axle ratios.
My question is whats the best way to fix this high speed/rpm sputtering. I also have a holley 670 street avenger with large jetting (90 something). Would the street avenger be a better choice for this engine because its supposed to be a performance carb. I was also thinking about a 650 or 750 double pumper but I don't know if that will be too much for this engine. Or am I looking at this all wrong and ignoring the fact that I might need a higher volume fuel pump?
Any help or suggestions would be great.