72 mfi stacks

I'm planning on putting the mfi back on my car. Are these the correct stacks? 901 110 309 OR

The 1972 stacks are plastic, rather than magnesium as on the earlier cars. I can't tell from the photo what yours are. Also, the throttle size is larger on the S vs the E and T.

Thats what I thought. The top pieces are plastic as you can see I have a few chips in them. The main part of the stack is metal.

I guess I'll keep an eye out for the correct ones. Does anyone have a part #.

Thanks for your help.

Also is there a differece with the throttle bodies between the T, E, and S?

I do know I have a S pump.

Thanks again.

DM,

You can measure the diameter of the Throttle body openings (side against the heads and the stacks) and also measure the bottom and top opening of the stacks. Then compare them to this chart from a very helpful Pelican post.

Throttle body and stack measurements

Should give you a better idea what you have.

FWIW, both plastic stack on my '72 911S have a number cast in them.. 911.110.312.1R Dunno for sure if this is a part or a casting number.

Well my stacks measure 38mm on the bottom and 46mm on the top , so that looks like a 69S stack. My throttle bodies measure 36mm on the bottom and 38mm on top, so they are S specs also.

The throttle bodies seem tight and there is no light shining through when held up to the light.

I think I'm going to wait till next winter to tackle installing the MFI. I want to drive the car this summer and can wait for this project.

Thanks for the help. Now I know what I have. I still need some small stuff but I'll just keep my eye out for parts.