MFI for 3.0/3.2

daloff · 12-28-2003, 04:40 PM

I would like to change over from the 46mm PMOs that I am running with my short stroke 3.2 and use MFI. Which early pumps and stacks and throttle bodies etc do I need to purchase and then I know some upgrades need to be done to the pump stacks and, throttle bodies etc. Can anyone with some information start me in the right direction or point me to a site or link or thread that would be helpful.

Thanks
David

Bobboloo · Bobboloo's Garage

Paul Thomas has a 3.5 MFI car. He's a regular on the board. You might e-mail him.

The 2.2 mag stacks would probably be your best bet since they are the beefiest. The E and S version have the same outer diameter so you might as well get the E stacks since they are cheaper. Same goes for the throttles. The E and S throttles are identical except that the E tapers from 38mm > 32mm and the S tapers from 38mm > 36mm. Both have 38mm throttle plates.

For a reference point. The 2.7/3.0RS intake setup flowed as follows.

Stacks 42mm>38mm
Throttle plate 38mm
Throttle bodies 38mm>36mm
Intake port 36mm

So my guess for a 3.2L would be something like.

Stacks 46mm>42mm
Throttle plate 42mm
Throttles 42mm>40mm
Intake port 40mm

This would be doable on 2.2 mag stacks.

The 2.4 pump was identical for the T,E,& S as well as for the 2.7RS and 3.0RS. The space cam was the only difference. So any 2.4 pump is a starting.

Elombard · 12-29-2003, 07:14 PM

The big problem is running the pump I think. You have to change the heads and cams to run a belt for the pump. The pump is timed off the cam so there has to be a wheel on the end of the cam for a belt. So it gets very expensive in a hurry. Of course it is very cool when it is done. I believe that the two big MFI shops in So. cal could talk you through it, I bet they have done it a number of times. I think one of them is called Pacific injection.

Bobboloo · Bobboloo's Garage

As for running the pump you have two choices.

#1 (cheapest route) Buy the little adapter that converts a non MFI cam shaft and tap the end of the left cam. Then just screw on the adapter and drive gear.

#2 (expensive route) Buy some 3 bearing MFI cams with the appropriate grind and a pair of 3 bearing cam housings and swap them out.

I'd go for option #1. Even if you can't locate this part it would be very easy to fabricate from a billet.

Another thing to address. The injectors. Once again you have two choices.

#1 (cheap route) Buy a Madonna air filter setup from Jerry Woods and install the injectors in the top of the air filter assembly.

#2 (expensive route) Pull all your heads off the motor and have the CIS notch welded up (if it hasn't been already) and then drill the heads for the MFI injectors.

Once again I'd choose option one not only because it's cheaper but because it actually mixes the air and fuel better.

daloff · 12-30-2003, 02:16 AM

Heads are already tapped for MFI injectors. So I'll go that route. I know Elgin cams can tap the end of the cam in prep for the pump drive.

Thanks

Elombard · 12-30-2003, 02:26 PM

Hey Bobboloo any idea how much those airfilters are from JWE?

Wayne 962 · Wayne 962's Garage

Probably about a $5-$6K setup when you include all of the custom stuff. If you're looking for added performance, then go with Engine Management. If you're looking for the vintage MFI look, well, then that's a different story...

Also, I could be wrong, but off the top of my head, I think that all 2.2 stacks were plastic. I think that only the '69 stacks were magnesium.

-Wayne

Bobboloo · Bobboloo's Garage

There were three versions of the MFI stacks.

1. 69' 2.0L Thin wall mag stacks that only mount on 69' throttle bodies because of the smaller bolt spacing.

2. 70'/71' 2.2L Thick wall mag stacks that have the wider bolt spacing that matches the 72' thru 75' throttles making them interchangeable.

3. 72' thru 75' 2.4/2.7/3.0 Plastic stacks with the same bolt spacing as the 2.2L version.

P.S. I also read that you can actually update the 2.2L pumps with a space cam from a 2.7RS pump. So the 2.2L and 2.4L MFI systems have a lot in common. The one year only 69' 2.0L MFI is the oddball. The pumps can't be upgraded and they must use 69' throttles but a matched set of stacks and throttles can still be used to build an RS motor.