I think i read in a thread ages ago but can't find it now, that you can use some sort of switch to control the butterfly in the dual length au manifold on older model engines? Also does the fuel rail have to be an au item or does the XG one fit, ie do i need a complete manifold, fuel rail, injectors, and wiring as a unit, or do the older components fit?
The reason being i'm going to build an engine with and au bottom end 40 thou over, with the au inlet manifold, but i'm using the head and ancillaries off my XG engine thats already been worked over, and i'm still going to use the EEC IV ecu thats in it atm.

If anyone could point me in the right direction would be great?

hi
there is a rpm switch you can get from jaycar that you can set the rpm is switches but it doesnt work to well.
as the early ecu has a different fuel and timing map so if you use the later manifold with the early ecu you will have alot of pinging issues..

have a look at this link.
http://www.fordmods.com/forums/documents.php?doc=85
ive got it all to work in a ea with the el ecu...