This isn't 3rd gen related but I really need help. My other ride is a 73 Chevy pickup. It has a 71 350 that has been converted to HEI. I decided to give it a tune up the other day, but when I was done it was running great. Today when I started it up it was running very rough, barely idles, but runs. I changed the cap rotor wires and plugs. I did notice the coil looks as if ithad been dropped or something. The outer metal square (can't think of name) was separated from the epoxy on the windings. Could this be the problem? It was very hard to start. Had to floor it just to get it to start. Or could I have unknowingly swapped wires around on the firing order? Like I stated before, the truck ran great after the tune-up. It also has a history of running bad when it is wet outside, and it has been snowing here for a couple of days. Should I get a new coil? Should I rewire the firing order? Or both? By the way the motor is from a 71 police/taxi 2bbl fullsize Chevy car. It has a 4 bbl(don't know year or model) and converted to hei (red and yellow primary wires also don't know what year). I didn't set timing, don't know what it should be. The truck is a 3 speed manual and originally came with a 307. Could I set the timing to any 350 timing? Thanks in advance for any help/advice given

 

Bad running on wet days is a classic case of moisture getting inside the distributor, usually through a crack.

Double check your plug wiring. Go throught the firing order one at a time, tracing each wire to make sure it goes to the right cylinder.

Definately check the timing. Start with a basic 350 timing and go from there. Maybe 10 degrees, I don't know, just a guess. If you hear any rattling during acceleration, back off the timing! Also, maybe the dist. hold down bolt loosened up and let the timing change; make sure it's snug.

 

JB,

389 is correct about the moisture affecting the distributor. It can also strain a weak ignition coil and weak spark plug wires. If your coil has signs of physical damage, you should consider a replacement. Make sure you get a coil that is designed for the HEI moduile you are using.

Inspect the plug wires closely, and repalce them is there are anyt signs of weak insulation, physical damage, or ozone hazing on the outer jackets. I would suspect the firing order is correct if it ran that well immediately follwing the tune up.

 

Thanks guys. I did check the firing order, it is correct. Everthing is new except for the coil and module. It has been pretty nice here for the last couple of days so starting has been easier. I will try the coil and tell ya if it solves the problem.