I found a set of SU carbs as I am planning to convert back to the double SU setup instead of the Weber 38. I’ve read that a B20 with double SU works best with a K or even better a TT3 type camshaft. I don’t know what type my engine has (finding out would mean taking the head off) so this could be a bit of a guess, but I can always go back to the Weber. It should have a C type installed and it should be a working setup. I’m also aware this is a 2-bolt type and a 3-bolt type would be better.
Offcourse the setup is not completely original as the engine is supposed to be a B18. The B18 got replaced a long time ago probably back in the States by a B20 with the bigger valves with a little more power. So unfortunately no matching numbers for the engine, but the M40 transmission is. Anyway, the double SU will looks much better.