Gazz, I had a similar problem when I first moved to Arizona with the hot summer heat. I think that the problem was vapor lock and a new fuel pump solved the problem.
I found that it was almost the same price to buy a new fuel pump as compared to buying a rebuild kit. Unless you need the double action pump for your wipers, I'd stick to a single action.
If you want a double action pump, keep your eyes open on eBay. I got lucky about three months ago and bought a NOS AC pump for $7.95.
I also had the non-magnetic red sand. Mine turned out to be coming from a disintegrating tank liner. My tank had been lined at some point in its life long ago. A new tank solved the problem.
Many 'bolters install a filter in the fuel line ahead of the fuel pump. Many highly recommend it.
Matt
