Hi my friend needs your help he just bought a 1974 dodge pickup with the slant six in it. It cuts out and stalls when you start off. It is not firing on the number 5 and number 6 cylinder. When you pull the plug wire on those two cylinders it makes no difference how it runs. The compression reads from 1 to 6 is 125, 130, 140, 121, 112, and 116 and it has good spark it looks like it has new cap, rotor, plugs and wires we checked and they are getting spark the timing is good. We cant figure out what the problem. Any help will be apprecated.