9/64 Circlip found at the woodland orchard supply seems to secure this decomp.
Jbot your level of expertise is so amazing. I will keep your wisdom stored. I borrowed the Athena piston from cheetachrome and he commented that the ring land porting could be improved upon. Now I see yet another reason to get stuff like that exactly right. Wow
But back to this. Next step is to ascertain the head actually fits.
The decomp pathway on the derby is angled where the gases exit to the groove milled into the face of the head. That leaked for cheeta leading him to plug the decomp off. If it leaks there I was wondering if a dab of jb weld would work or drop a dab of metal with a tig.