Mohuska I know that TWM says 58mm, thats on the inlet, what is the size of the throttle plate at the base. I understand that the manifolds had to be special or the webers to seal, not enought sealing surface. 48mm manifolds where hogged out. Next time you take one off measure the throttle plate. 2 3/8 is 58mm , theopening in the manifold needs to be 2 7/16 to cleareverything when WOT and the engine at operating temp. The only person I know running 58MM Olbergs has had this problem with gasket seals. I am looking at the same setup. I like the 10-30 hp in mid range over a carb. And the tork.
Rick Lake