Hey guys new here and i have been having this sudden and strange issue, about a month ago i picked up a 63 nova 4 door with a 327 and th350 transmission it was converted to and HEI distributor and has been running great but a few days ago i was coming home from work and when i was coming to a stop the car started shaking really bad and running rough, when i started to go again it was popping and sputtering till i got past 2500 rpm then it seemed fine, i got home parked it came out side about 30 mins later and started it up and idled fine gave it a few quick revs then idle went to crap and misfiring played with the plug wires and made sure everything looked good stated it back up and idled fine gave it a few quick revs and bam rough idle and misfire and if i hold the rpms at 2500 you can hear it miss, since this i have changed plugs autolite coppers cap rotor and new coil plug wires are only a week or two old and changed fuel filters and still the same but the weird part is that sometimes it will idle fine till i rev it then back to rough missing idle anyone have any ideas?

 

some specs on the motor and this is how i got it, 327 block with 70cc 350 heads edlebrock maifold with an edlebrock 1406 600cfm card HEI distributor with MSD cap and rotor and Accel coil with Accel 8mm wires and Autolite copper plugs gapped to .040

 

update: i sprayed water around carb and intake manifold to check for vacuum leaks and nothing the car has a for sure miss but cant figure out why, if anyone can help please do.

 

Sounds to me like crappy gas.

 

Nope was not crappy gas turned out to be a dirty carb i took it off today and pulled it apart and cleaned the jets and floats and reset the floats and put it back together and bam misfire at idle and under load is gone running great again i would have never thought a dirty card would cause a miss fire but i was wrong.

 

Previous crappy gas.