Hey guys My names Greg and I'm having a problem with my 350!
Background of the motor first. Rebuilt long block rotating assy. from summit racing. Cams numbers - lift is .450 intake / .460 exhaust. Camshaft duration at 050 is 222 degrees intake and exhaust. Lobe centerline is 114 degrees. Unsure of cylinder head specs other then I believe its a 72cc combustion chamber. I was told 8:1 compression ratio. Road Demon 625 carb, Edelbrock RPM airgap intake, MSD pro billet distributor, MSD 6al-2 ignition box, MSD blaster 2 Coil Pack.
Now to the issue. rolling on the throttle slowly and the motor picks up fine. When under harsh accel from idle or very low rpm it wants to fall on its face, die, and backfire until 2000rpm or so. I cant honestly tell the difference between backfiring from the intake / carb or exhaust as I'm relatively new to hot rodding sorry in advance.
Solutions tried so far. I've had the timing anywhere from 10 base all the way to 30 base in 2 degree increments. The higher timing seems to fix it slightly, but I lose almost all top end power. I did some research and found that with the air gap intake sometimes you need to go larger on the accelerator fuel pump nozzle. The carb came with a 31 stock so I went to a 35. No Dice, if anything made it worse. I also changed out the secondary diaphragm spring and went lighter. really didn't make much of a difference other then they kicked in sooner.
Now I do have a new set of heads on the way Trick Flow super 23 195s with a 64cc comb chamber. don't know if that will help much or hinder it.
Any Ideas or suggestions further questions of anything else I missed in the description would be greatly appreciated!
Background of the motor first. Rebuilt long block rotating assy. from summit racing. Cams numbers - lift is .450 intake / .460 exhaust. Camshaft duration at 050 is 222 degrees intake and exhaust. Lobe centerline is 114 degrees. Unsure of cylinder head specs other then I believe its a 72cc combustion chamber. I was told 8:1 compression ratio. Road Demon 625 carb, Edelbrock RPM airgap intake, MSD pro billet distributor, MSD 6al-2 ignition box, MSD blaster 2 Coil Pack.
Now to the issue. rolling on the throttle slowly and the motor picks up fine. When under harsh accel from idle or very low rpm it wants to fall on its face, die, and backfire until 2000rpm or so. I cant honestly tell the difference between backfiring from the intake / carb or exhaust as I'm relatively new to hot rodding sorry in advance.
Solutions tried so far. I've had the timing anywhere from 10 base all the way to 30 base in 2 degree increments. The higher timing seems to fix it slightly, but I lose almost all top end power. I did some research and found that with the air gap intake sometimes you need to go larger on the accelerator fuel pump nozzle. The carb came with a 31 stock so I went to a 35. No Dice, if anything made it worse. I also changed out the secondary diaphragm spring and went lighter. really didn't make much of a difference other then they kicked in sooner.
Now I do have a new set of heads on the way Trick Flow super 23 195s with a 64cc comb chamber. don't know if that will help much or hinder it.
Any Ideas or suggestions further questions of anything else I missed in the description would be greatly appreciated!