Hi Eric, I am sure I replied to this question a number of years ago , in the 1970s I ran my Birmingham Scott on a 389 monobloc, you will have to make a wedge shaped manifold, start off with block of aluminium approx 1 1/4″ thick drill and counterbore for 3X 1/4″ whit allen screws to attach to the crankcase, then machine the carburettor face at an angle so the carb sits at a more horizontal position and drill and tap for fixing studs at 90 degrees from this face, you will have to blend the centre through hole to align carburettor and crankcase, my carb was 1 3/16″ and needed quite big jets to compensate for the slower air speed through the carb, hope this helps, by the way George Silk used to sell Concentric carbs and manifolds as an upgrade for Scotts. Alan Noakes. scottworkshop@hotmail.co.uk
