The W-1 will have a smaller bolt pattern than the 53-62 235 Offy intake, so slotting the holes on the carb would be necessary. Otherwise using an intake made for the 216 could be used, but the ports on the intake would be a little smaller, so the locator rings won't work. Either way, you have a little fab work to do. Typical hot rodding.
Is it smoking all the time, or just at start up?
Is it using oil?
Any water present in the oil?
Does it run hot?
I am assuming you mean someone split the original exhaust manifold? if so, the heat riser area is different between the 216 and later 235. fentons are a better choice, but expensive.
This may not be the best thing to do performance wise (minor) but would be the cheapest/easiest, but using a 2x1 intake designed for a 216 would allow you to reuse your exhaust, should have the smaller carb bolt pattern, and if you use some copper RTV when bolting up the intake, you shouldn't have any leaks. Or have a machine shop bore out the intake ports to match the later 235 rings. If you go this route, I would recommend trying to scrounge up a Tattersfield 2x1.
Otherwise, Fentons and a correct late 235 intake and w-1's or the holley/weber 2bbls would be the way to go. Your choice.
