rebuilt 350 skipping

just rebuilt 350 running fine for 2 weeks.All of sudden skipping on #3.changed plug and wire did not fix.wire is firing.any idea what could be wrong.

you might also check if your valves are too tight. Sounds like ignition problems, but dont rule out a stuck lifter or tight valve.

If It Was A Broken Valve Spring.it Would Be Making Noise Right?checked Compression 125..

I don't know what car you have it in, But let me tell what happened to me with my wifes Vett. I thought that it would be a good Idea to up grade the ignition in her 72 Vett. Now it has a new engine in it and ran ok but not as good as I thought it should. So I dropped a 1000 bucks on a new MSD gear drive distributor, MSD box, coil, wires and spark plugs. The Vett still had a miss in it, I thought what the ____ . I spent all this money and it still dosen't run any better. So I called Summits Teck Line This is what I was told.
The older cars that were originally fitted with a points type distributor ran a resister type wire from the ignition switch. New this would let the car start with 12 volts and then back the volts down to about 4 volt after the car started. This keeped the points in the distributor from burning up or melting down! Thus my MSD is getting choked or robbed of the power to run right.
The fix is to replace the resister wire to allow the full power to reach the MSD. Hopefully this will help some one.


~ Vegas ~

finally fount it valve was to tight.just didnt make sense why it would tighten up.. anyway that was the fix..thanks

Glad to hear you found the problem. I have seen the tight valve miss show up before out at the track. Mostley a problem above 3000 RPM's. Is it Hydraulic or Mechanical lifter?