Thanks for your responses guys,
I will try new plugs on the weekend. It's the only thing that I haven't changed and I really don't how old they are, as they were on the car when I bought it two years ago.
If this doesn't fix it, I will move on to the wires and distributor, although I would like to keep the stock ones.
1969 SS-350 Hugger Camaro
1995 Black Camaro