The Adamisin set up was a ' X ' onto the front face of the big end . Something like 1.2 mm radius . As in , if youd clamped two rods back to back , and drilled ,youd have half a thing on each , as it were .
ALSO a nylon ' T ' pad , plugs in the crank big end end , to stop the rod walking aft . Lee Machine Shop does these .
We used to run OSes No Nitro , in the early 70s . No Problem . a 10 x 4 three blade Tornado , if you want to fly slow with a light plane , or a 11 x 4 , in the our stroke .
. So maybe half of it IS the slop for & aft , in the 30 & 35 . As in its a H 29 R rod , wot gets heck , so should be o.k. .
Multi Fit .
a 32 SX rod is bushed , and looks vaugely like it might fit perhaps .