Not enough info in question; howver, if you have a carbeurator, then the choke needs to be WD40'd (or repaired). If you have fuel injection, then it's probably water in fuel. -DRS.
To send a spark the the proper spark plug at the proper time.
.030
.035
1,3,4,2
Whats the model number??
Most of these were .045 but you should check with a AC spark plug application book.
.030 - .035
.039-.043
.054 inch
The 1986 Chevrolet 350 cubic inch engine spark plug gap is .027. Most spark plugs will be pre-gapped by the spark plug manufacturer.
Take it to a dealer
.54 Thousands........