My mate adam has a few, he gets some of his spares through USA, in Wymondham 01953 601410.
Just don't expect speed, just because of engine size, although mpg can be surprisingly good 25+.
He has a 76 firebird esprit(camaro), 77 stingray, and s10 stepside at mo.
The vette is a small block(5,7) and std came with TWIN 1150 double pumpers loads of soot from exhaust and around 2mpg.
Now on a 650 vac secondary, so 25mpg is not a problem, spares are often a lot easier to get/quicker than present day ford stuff from dealers.
Nice cars though, shocking handling and brakes/build quality.
tabetha