got a replacement manifold for my 235 from Auto Services Colne.UK.£50 for a set. I've had to sepparate inlet from exhaust before and realy didn't want to go there again,so I left as is,the inlet on the 'new' set has a shallower plenum chamber,square bit the carb sits on,engine appears to run alot sweeter with this setup,its on a 58,235 chevy sedan with single barrel Rot' any ideas?