Stroker Motor wont Rev pass 5200Rpm

I would start with checking the rev limiters. If the MSD unit is a dual limiter (launch and run), what is the launch limit set at? If it is set around 5200, that would be very suspicious. You could try changing the launch limit setting and see what happens.

Or, either the FiTech or MSD units might have been accidentally set to 6 cylinders, because 5250 is exactly 6/8 of 7,000? You could start by verifying both the FiTech and MSD "cylinders" selections are set at "8". If they are, I would start with the MSD box and reset the rev limiter to 6,000 and see if the engine is still limited at 5200-5300. Then if the engine is still limited ato 5200-5300, reset that limiter back to 7,000, and set the FiTech unit to 6,000 and see what happens. Even if both the FiTech and MSD units were set correctly to "8" there could be an internal circuit problem that set it to "6".

Next, I would look for a fuel problem.

I don't know whether a cam/spring problem would cause a sudden and repeatable rpm limit. I would think it would be more gradual. IMM coould answer that question for you.