Ford 250 crossflow alloy head 4 barrel manifold,This new model manifold is a great all rounder,small port & plenum for greater Airspeed & acceleration.The manifold has a shaped plenum floor & wide runner for better fuel & air distribution to all cylinders.The manifold ports are tapered from the manifold face & are under gasket size to allow for match porting or straight bolt on.The tapered port runs back down the port about 30mm to create a funnel effect for engines running in the lower RPM range or can be hogged out to near on 48mm for all out performance/race application.The AS0016 accepts squarebore carby only.