There are a few more powerful 1/2A engines out there today, than back then. Unless you have the standard two and a half bushels of various Medallions and TeeDees in your shop, consider a look at some of them. 'International' half-A seems to include 1.0cc (0.061 cu in) and there's another useful handful of power right there.

I think a shop in Canada still has BigMig engines in stock, but not everywhere in the USA seems able toget them easily. They are modern metalurgy so modern RC fuels go well, if they have enough nitro...

Welcome home! and Happy X and NY.

\BEST\LOU