Join Date: Mar 2002
Location: Austin, TX, USA
Sounds like a couple of plug wires are reversed. The firing order is 1-8-4-3-6-5-7-2. Referencing from the drivers seat...Number 1 on the distributor is at the 11 oclock position. Number one is the front left. Left side is 1,3,5,7 from front to back. Right is 2,4,6,8.
While your inspecting the plug wires, I'd remove the plugs. It will tell you more about your motor in case the plug wires aren't the cure. If the plug wires are the cause, it will be an educational exercise to help you next time.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI