Spent all afternoon searching on the internet with a couple of possible routes to go with conrods, but I like the sound of fitting rs focus rods with the blacktop pistons using bushes in the rods for the smaller gudgeon pin, as I should be able to sort that myself! And it should drop the pistons down 3.8mm which will allow plenty of boost. I need to calculate the compression on that to make sure it's not too low, hopefully about 7.0:1 or above.
Alternatively silvertop rods can be modified too.

Ebay here I come, but in the meantime I do have a set of silvertop rods and pistons but the shells have spun on the rods, so no good to use, but perfect to machine and play with to see what I can achieve!