B20 is an overhead valve, pushrod engine. The B23 is an overhead cam engine. Never heard of anyone putting the OHC head on an old block.
If you have a good B20 but don't want injection, B18 and B20 engines were all available with twin or single, SU or Solex carbs. Should be easy to find, fix and fit those onto the engine you've got. You'll make a profit selling the FI system too.
If you have a good B20 but don't want injection, B18 and B20 engines were all available with twin or single, SU or Solex carbs. Should be easy to find, fix and fit those onto the engine you've got. You'll make a profit selling the FI system too.