My best guesses would be:
A problem with the distributor cap or HT leads - since the spark plugs have been recently changed they could have been damaged if they were quite old and "ready to go" when they were moved.
-or-
A problem with fuel delivery eg. a simple part like a fuel pump/filter, or in a car that age it could be a carburettor problem. I used to have a 1990 Toyota and a carburettor problem eventually killed it off, but if I had my time again I'd spend longer investigating if it could be fixed.