MFI Induction Chart

I just posted this at Pelican and I thought I would post it here as well for the Early S database.

I measured all the the induction setups with the exception of the 72/73' S/RS setup stacks which I did not have available to measure. My guess is that they are the same dimensions as 70/71' S stacks.

The stacks were made of magnesium until 72' when they started making them out of plastic.

The throttle bodies in 69' had a stud spacing of 66mm. From 70' on they used a spacing of 72mm. Therefore throttle bodies can't be interchanged between 69' and the later years. From 70' on they are interchangeable. i.e. You can put a 70/71 E or S stack on a 73' T throttle body.

The 69' magnesium stacks had the same outer dia. on the E and S stacks. The center bore is what is different. Same is true of the 70/71 mag stacks. The 70/71 stacks however have the most material even though the S stacks have a smaller inner top opening dia. than the 69' ver.

The 70/71 stacks E or S therefore would be the best candidates for a large displacment motor in which you plan to bore out the stacks.

As you will see in the chart. All the throttle bodies start with a 38mm bore and taper to their respective cylinder port. Therefore you could bore the bottom of a T throttle body from 29mm to 36mm and use it for a 3.0RS if you chose to do so.

In the chart below you see the numbers 1 thru 5. These correspond accordingly.

1. Top opening of stack
2. Bottom opening of stack
3. Top opening of throttle body
4. Bottom opening of throttle body
5. Cylinder intake port.

This shows the flow pattern going down into the cylinder.

Year..69'.......70/71'.....72/73'

T

1.......n/a........n/a......35mm
2.......n/a........n/a......32mm
3.......n/a........n/a......38mm
4.......n/a........n/a......29mm
5.......n/a........n/a......29mm

E

1.......39mm....38mm....38mm
2.......35mm....35mm....35mm
3.......38mm....38mm....38mm
4.......32mm....32mm....32mm
5.......32mm....32mm....32mm

S

1.......46mm....42mm
2.......38mm....38mm
3.......38mm....38mm....38mm
4.......36mm....36mm....36mm
5.......36mm....36mm....36mm

2.4S, 2.7RS and 3.0RS all use the same MFI setup. The only difference is the space cam used on the 2.4 motors. The 3.0RS setup is identical to the 2.7RS