[wilf]

Nitrous? - I think that is our biggest clue!

If you had cast or hyper pistons, they are not going to stand up to nitrous as well as forged. Also, if, when you strip it, you find a piece of top piston ring land missing, then the ring gap was too small, and the extra heat generated by the NOS butted up the rings. Ring gaps need to be bigger for any kind of power adder.

Your 383 stroker approach sounds good. But you could always go to one of the Dart/Merlin blocks that allow bigger bores, and go for more CIs? You might miss the torque you have now otherwise.

At least it's nearly winter.