Jerry, how much does a set of custom pistons cost?
I did some poking around and found a couple things that might work for you (based on specs you gave to match with the NASCAR rod) with some modification. But they aren't exactly cheap.
Packard piston - thttps://egge.com/part/egg-1000-e152-8/
The overbore options get you into the range of a 235. Not enough compression height. Could you cheat that much out of the crankshaft offset grind to compensate?
Flathead Caddy piston -
https://egge.com/part/egg-1000-e107-8/Again, the overbore pistons gets you into 235 range. Closer on the compression height. Not sure how that chamfered top would affect compression.
John Deere 2010 piston? - Don't have the part # handy and couldn't find a compression height. But it's 3.625 and certainly looks like it might be "tall" enough. For that matter, lots of old tractor pistons have a taller appearance (comp height seems to be the tough part of the match, most auto pistons are shorter)....and there might be something out there in the tractor world. I haven't found any literature that lists the specs.
