Hi,

I had a 74' Fiberform with a 302 Ford engine that sat for many years
before I bought it. The first few times I used it, it idled fine but
backfired at more than 1/2 throttle. The problem was the springs for
the mechanical advance in the distributor had rusted and were weak,
allowing the timing to over advance. New springs fixed that problem.

Also, since it sat for so long, carbon started flaking off the
pistons/heads. It took several months of running, and cleaning plugs
before the carbon worked its way out. Meantime, I would foul a plug 2
or 3 times a day.

Hope this helps,

Ron