Hey Cats,
Today I was putting on some highway miles and stopped to get something cool to drink. Afterwards, I was attempting to get back on the highway, and my '78 backfired a few times in 2nd, and a few times in 3rd. Just about conked out it felt like. Any suggestions??

 

was it backfiring through the Carbs? or through the exhaust?

 

It was backfiring through the exhaust, but it felt like it was going to stall on me. I have had the injectors replaced in December, new master and slave cyls in January along with a tune-up, incl new plugs. I was thinking I should maybe get a new ignition coil, this may help, but I am not certain.

 

Coils work or don't work, 99 percent of the time their OK.

I agree with the timing chain idea but don't assume thats it right off.
Check your timing, its possible that the distributor is not tightened down and the timing is off.

Check your battery posts, make sure the terminals are clean, the Z's are sensitive to current drops from bad connections and that can make a problem.

Too lean of a mixture will cause backfiring so look for leaks in the vacuum system, check your fuel pressure, etc.

My latest Z started coughing and backfiring on Thursday, couldn't get it to go up a hill to the house. Looked really bad!!!!

Problem was a clogged fuel filter.