hello all, I have a very strange problem that I can't seem to get rid of. It's on a Chevy 396 that's in my '78. A couple weeks ago I was getting ready to smog it, changed the plugs and oil, and fired it up. It backfired through the carb, and then started running poorly and flooding. Took the carb off, the float was stuck, fixed that, still the problem. Changed the: plug wires, plugs (again), cap/coil (HEI) rotor, vacuum advance cannister, PCV, any suspect hoses, swapped carbs. Can't seem to knock the problem Also checked time with the marks on the balancer and it doesn't look like the chain or distribnutor jumped any teeth. 've been trying the past couple weeks to get it running right and nothing seems to completely cure it. As of right now, it starts right up, runs smooth at idle, and will rev to 4,000 RPM strong and steady. The trouble comes when accelerating. it will get up to speed if you give it light throttle. Granny low and first gear accelerates no sputtering or backfiring, 2nd gear and third gear if you try to accelerate too quickly it pops and shutters through the carb, and the truck bucks. Mash your foot down it will sputter a bit and then go strong. Forgot to mention, it's a SM465 trans. That's about the best description I got. In a certain RPM range (1000-1500 with the 38" boggers on, 1500-2000 with the stock tires on), if it is loaded it pops. Barely any visible smoke since I put thicker oil in. The motor has about 200,000 miles on it, and has always burned oil but just keeps going and going. It ran decent before this happened. My best guess is a stuck lifter, bent pushrod, or valve, or broken or weak valve spring on one of the intake valves. Really don't want to pull the valve covers because that means moving the AC and everything else. any ideas? thanks!