EA82T 3 plug 4 plug manifold difference

[steptoe]

Vacuum advance is used for the 3 plug ECU only, some other smarts is used on the four plug ECU motors for advance/retard.

So, the inlet manifold itself is not different, but the vacuum lines that share the same structure with the fuel rail are.

It has been bugging me if I need to use a 4 plug rail with my 3 plug gear where does my advance/ retard supply come from then?

Answer seems to be that follow the vac advance from dizzy it sources it from the LHS of the middle of throttle body pair of suckers off the manifold (or was it TB?) at the front. The vac advance also T pieces off to the pollution charcoal canister, so if you or I strike no vac advance for 3 plug dizzy for some reason (playing with quarter of a century old cars) can source suitable vac advance form charcoal canister line.