stange type 4 big bore kit..?

[elroocky]

hello guy's we have found an old NOS kit of cylinders and pistons in diameter 100mm, but without precise mark, the kit is made for 66mm crankshaft and boring is 99,98mm. the boring is flat but renforced out of matter to make release in the pistons for the valves (just for 2 valves)
the cylinder is lined cast iron with an aluminum envelope. the pistons are just located by "UP91" and a code "FF" on the side.

the pistons look like wiseco, short skirt and are released around the sides of the axes, the axes its in 24mm
does somebody knows something more than us about this kit..? factory.? a name.? built by who..?

thanks for help

david