I have a 408 small block, 4200 stall with a 750 double pumper 76-80 jets and Chrysler electronic ignition. It has run well in the past. Now it does a burn out fine but when I leave and it winds up, it craps out and misses until I let off. It has a new cap and rotor on it and I put new plugs in it. On the new plugs it made 3 pretty good passes but felt like it was not winding real strong. Then the 4 pass it craps out. I looked at the plugs and they are not fowled and are brown off white. The carb has always worked well and I haven't touched it. I have a carter electric fuel pump on it set at 6psi. Anyone have any ideas what my problem is? Thanks