Ok, here's yet another setback on trying to finish the wagon by Saturdays HRH. It may be nothing, but it drives me crazy not knowing. Ok, here's the skinny, Boring, plain 100% bone stock 350, 97 vortec. Brand new HEI, new Taylor wires, 34 degrees total advance. Brand new Edelbrock 1406, elec choke. Ram horn manifolds, no exhaust yet (going Monday). I have 5 lbs of fuel pressure. Cam is not going flat, Breaking it in with Joe Gibbs break in Racing oil, high content of Zinc. Motor has 20" of vacuum, no exhaust leaks, all new vacuum lines. Also, I have ran the valves several times and checked the firing order 10 times. When I am trying to bring the motor up to speed, say 2000-3000 rpms, it pops sporadically out the exhaust, I can see flames like an after fire. Seems like it is rich and has unburned fuel dumping into the cylinders. I can see this in the vacuum gauge. It idles fine. Should I just quit trying to tune until after I get the exhaust finished? I don't know if back pressure has any effect on tuning? I don't know squat about Edelbrock carbs, is there any tuning I can do without buying a tuning kit? Thanks in advance......I am burned out on this project, but I am pressing through.