Rover V8 inlet manifold 3.5 and 4.2 - same ish ?

[mad_pete]

I have a a ported 3.5 rover v8 inlet manifold.  How interchangeable is that with a 4.2 one?

I’d want to keep the cover and the fuel rail from the 4.2 but use the manifold from the 3.5. Are they the same enough to do that ?

This is the 3.5 one on the bench.

[Bowie69]

I believe they are compatible, the base inlet almost the same going up to 99 on the P38, just maybe some slight differences in coolant pipe and temp sender/sensor placements. 

[FridgeFreezer]

As Bowie says, the machining is subtly different (some holes not tapped later on etc. as stuff was omitted) but the basic castings are identical.

3.5 Flapper left, 3.9 Hotwire (same as 4.2) right:

[Hybrid_From_Hell]

Yes 3.5 will fit gas 8th injector (blank off) and doesn’t have stepper gubbins on rear face but can be retro added 

 

linkage between 3.5 and other is bigger and different but can be swapped about