My guess is the head studs would be the weak link and it will blow a gasket. Sure hope it doesn't wreck a rod but there really is only one way to find out for sure.
Sounds like a plan, a 2.5hp shot would be a lot for these little machines, I bet the stock con. rod would pretzel with much over 2.5hp of NOS.
The smallest jet I can get is a .009 and with a dry shot that will give me a bit over 3hp. With a wet shot (which is generally my preferred route) I'll need to use the smallest jet for fuel which puts me at about .015 for a nitrous jet. That computes to a little over 10hp. I think 10 would cause immediate and very explosive catastrophic failure.
During covidcation I invested in the large stand up nitrous cylinder and a transfer pump for refilling bottles. Also started carrying nitrous parts on the KB site. Now I'm looking at all the vehicles in a whole new way. 😈