get some 10mm thick steel (off cut from steel merchant theres one near me charrged me £5),, then get the inlet manifold gasket, then draw round it cut/drill all the holes out so youve got a template of the gasket but in 10mm thick steel, measure the size of the inlet holes ,then go to sumwhere like central auto supplies and get a lenth of exhaust tubing in roughly the same size as your inlet holes or slightly bigger, then cut x4 lenths of your exhaust tubing to your required size (always measure up in engine bay), then use x4 silicone tubes to join each of your exhaust tubing to your carbs, (sounds missions but i made a 4 brach manifold in a day and half similar thing) ive got a decent 180amp mig welder thats what i used to make a 4 branch for my old car.
