3.0 to 3.2 mfi questions.

[Porschekid962]

I am starting to gather up parts for the engine that will be going into my 72 project. Starting point for the motor is a 78 30 sc. Plans for it are 98mm p&c's with pretty good CR, port matched heads, smoothed out, twin plugged, mod s cam, mfi induction. I am going to have the space cam in the 72T mfi pump replaced to best match the new motor setup.


My big questions are how do i go about retrofitting the MFI pump to the 3.0 case?
How do I get the drive gear on the cam housing for the MFI?
Are 72 911T throttle bodies meaty enough to have bored out to flow enough air for the larger motor? If not what tb's should I be looking for.
How much are mfi mag stacks for a set?
Aside from using mfi mag stacks what are the other options for the manifolds and intake trumpets?

What ballpark am I looking at on the parts?

Thank you all.

[spydr32000]

If you are starting with a 3.0 L engine you will need to tap out the plug in the back of the cambox from no.1-3 cylinders.
You cannot use cams from a 2.4 etc because they are a smaller diameter in the journal! The next decision is do you use new billet cams with the drive still on there,or, retro-fit 2.4/2.7 housings with 3 smaller bearings ,or, retain the 4 large bearing housings from the 3.0L.
You can bore out the throttle bodies but how much depnds on which ones your base items are( some have more material than others. This is something that needs to be done by a well experienced engineering shop.
EFI throttle bodies can be modified to suit as we have done this before, be careful to have a VERY good look before starting as you could destroy a perfectly good set of throttle bodies if not careful
Iwould suggest talkiing to Gus Pfister at Pacific Fuel Injection as he would be one of a VERY few people capable of giving you a pump capable of doing the job.

[Shuie]

good advice from Spyder.

The ports on your '78 heads will be fine. Figure ~$350 for the machine work to tap them for the MFI injectors on top of whatever else yo are doing to them. Your T throttle bodies can also be rebuilt and bored out to 39mm on the intake port side from 41mm. Find a set of '70-'71 mag stacks and take them 41mm-46mm. Camgrinder can add the drive gear to a 4 journal cam. Dont forget the breather cover, linkage bits, airbox, engine tin pieces, injectors, etc that are all MFI specific.

I dont know how much of this stuff you have to start with, but I would figure $5k minimum for parts & rebuild work if you are trying to source everything. Probably not what you wanted to hear, but let me know if you want me to add up the pieces Ive collected so far .

The cheapest way to do this is to wait for a complete big bore system to come up for sale. Ive seen two in the last year for under $5k and passed on them becuase I thought I could build one cheaper.

[camgrinder]

Do you have a set of cams allready? If not the late model billets have the left drive for MFI. Easy.
If you have cams and need the drive it can be added.

[Porschekid962]

I have the complete 2.4 mfi motor out of my 72T and a 78 sc 3.0 engine. I am not worried about engine tin or linkages. I already have the TB's as well. As far as injector placement do you have to put it in the heads? As for the cams I plan on going with spankin new pieces for the 4 journal 3.0 cam towers. Thanks.

[Shuie]

Ok, sounds good. You have all the small pieces. The heads will have to be tapped and you are going to need to either find a set of '70-'71 mag stacks to bore out, or bore you throttle bodies 39mm straight through with no taper and run plastic '72-'72 S/RS stacks.