clive45

I have a 3.9 MPI which I want to rebuild in the near future. Iwas told to rebuild a 4.0 instead.
What else needs to be changed besides the engine. ie manifolds,computer etc.
Any assistance would be greatly appreciated

SmokedEB

Depends, if you were goin to rebuild a 4.0, probably better to stick with the stuff that comes with it, assuming its a long motor, else, the computers are different, manifolds are the same if its MPI i believe, and i think the head is also common. Someone correct me if im wrong

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RIP 88' EA Falcon S pack
92 EB Fairmont - Retired POS!

EvilChief

if u wanna use the 3.9 log manifold and sesnors no need for new wiring loom and ecu. plug n play as afr as fitting the 4l engine

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SileNceR

yer if u use the ecu from a 4lt instead of a 3.9 mpi ecu, u will probably need a smartlock module and ignition barrel... easier just to use the 3.9mpi with the 4lt engine

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Rosewood EAII Fairmont 02/90. MPFI 3.9L (formerly CFI), 4spd BTR Auto. Skyline geared 3.45g open center 28 spline 4 pinion differential & axles. 2 1/2" Cat Back Exhaust. King Super Low Springs. Sound: Equalization and amplification by Clarion; Head unit by Sony, Front, Rears and Sub by Pioneer. Planned mods - t5, Extractors, Painting Grey Strips and new front and rear bar.

460Fairmont

3.9 was only the figure they were allowed to advertise them due to there being 17 different sized pistons 3.9L was the smallest capacity the engine could theoretically be the largest being 4.1L they still average 4.0L so you won't get any more power
it's not worth the extra hastle when chances are you could only be decreasing the capacity

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XD Fairmont, X-COP, BIG BLOCK still in bits
Injected RS2000 2 door (new toy)
EA Falcon, MPFI, 16in XR6 wheels,
2x1000W 12in subdoofers, splits,
TE cortina,Toyota Supra,TD cortina