MATH CLASS
Going to the Wiseco big bore kit takes one's engine up to 904 cc's, as we all know.
Putting a 78mm stroker crank in such an engine (92mm x 78mm) would give one a 1037cc engine. (92 x 92 x 78 x 1.5708 = 1037.0295)
This is assuming one can put that long a stroke in the Hinckley twin. If you could only go to 75mm stroke, you would get a 997cc result.
There are several factors to consider when stroking a Triumph twin, besides those listed in the original post:
1) Are the rods going to clear the crankcase as they go around?
2) Will the con rods miss the bottom edge of the cylinders?
(less a problem with an increase in bore size)
3) If a barrel spacer is needed, will the cam chain have enough play for the resulting higher cam location?
4) What formula do you use to balance this whole thing when you're done? (It will need to be balanced before assembly!)
Once someone figures it all out, it should be fairly easy, if not expensive, to stroke your America.
