This is the 3.6 with PMO 46 ITBs in my ‘74. I’m running Megasquirt controlling EDIS ignition coils and batch firing Bosche 30lb injectors. The motor is all stock internals and runs Billy Boat 1.75” headers with heat. I just finished cleaning up the engine bay wiring and fuel line routing. I also modified Zenith carb bases to fit the PMO itb’s so I can run a modified factory airbox. This is the later plastic airbox as the earlier metal ones are too tall to fit on a 3.6/PMO combination without more significant mods to shorten them. The plastic air box will just barely fit as it is about .75” shorter than the metal ones.
Previous dyno testing I’ve done on a 2.2s mfi motor showed the metal airbox improved midrange over K&N filters and gave up very little in top end hp. I also had my 3.8 pmo/Motec motor dyno tested with a modified metal airbox with 2nd 3” inlet to the filter on the back (towards the front of the car) of the airbox. The airbox proved to start to be limiting at over 325 hp and hard to tune and get a steady afr. That motor was comprehensively modded and made in excess of 370 hp, so the airbox was not used and I ran K&N filter hats on it.
The plastic airbox i’m using here has the same 2nd inlet on the backside and this motor should not be making more than 300hp if that. So I think it should work well. I plan to be refining the tune on the dyno in the next few months and will then be able to verify how well/not-well this plastic airbox works in this configuration.
Here’s a pic of the intake on the backside.
