Are the throttle bodies on an 84 300zx na with an automatic transmission bigger than those with a manual transmission? I am asking because a friend of mine said they are just a little bigger but this friend is not a very reliable source.

 

It doesn't really matter... a larger TB will do nothing by itself. We have plenty of threads talking about it as well. Anyway, read up on this: http://www.redz31.com/pages/plenums.html

 

You are correct. Your friend is not a reliable source. The throttle bodies are exactly the same.

 

it doesnt hurt to go with the 240sx TB it may be useless for stock cars but if you can get it cheaply i dont see a reason why not too.

 

What is the reason for using the 240sx tb?

 

On a stock Z31 intake... there isn't a reason. To answer your question, it's 60mm instead of the Z31's stock ~51mm.

 

i think it was 55mm nismo.

i would love to see an ITB setup for the vg though.