I cant say I know anything about A7's, but given they put late A10 cranks into A65's, I suspect that an A50 or A65 would go nicely into an A7 and provide a LJ crank, something I believe they never had on the A7.
I recall the A7 and A50/A65 stroke is what 1/2mm different?
I recently had a look at a "genuine" daytona A7ss motor and it had a very thick flange, something I wasnt aware of. I believe they did quite a lot of special parts for those...race rods etc.
Nice to hear people wanting to get their beesa twins flying!
Interesting. I'm building an A7 rigid roadracer (long-term project). If you have a choice, use later pre-unit cases and large-journal crank. What are limitations on internal engine modifications? Can bore/stroke be altered? My advice would be to spend your money on building a strong bottom end and then on cam/flowing the head. If you wanna go fast, you'll have to spend some money.