hey guys im looking at making a turbo manifold to suit my a12 and am wondering who has done this before? and whats involved?i want to keep it carby so ill have to get a su what size is suitable? what do i need to do and what parts do i need ?

depends really. if you want blow through or suck through

you need a manifold exhaust flange
then some steam pipe, weld them 4 to 1 and place a t3 flange on the end of it

place a su on the turbo and get some pipe and run it to the intake but i think this requires you to weld up some intake runners
a log manifold should be good enough for runners. although if your going to spend time making runners you may as well weld a few injectors taps and drill half-holes in your head for injection. and attach a butterfly valve in between the turbo/manifold.

just for the fact that su's are hard to tune right. you can also do it the other way where you seal up a weber and run your compressed air through that way via a turbo plenum, bit this method is supposedly dangerous and may also require a intercooler?