FI Plenum Design, MS'ing my 2270 Options

[Tom Perso]

Hey Guys,

I am designing a MS system for my 2270 (163.86b cam, 48x38 valves, future Triad header). I am looking at running stock intake runners and possibly making a new plenum to run my Ford TB (probably from a 4.0L Exploder/Ranger).

Are there any "design guidelines" that should be followed when making a new plenum, such as a certian volume required for engine displacement?

Looking at space requirements, I see running the TB on top of the plenum is the only way to go. That, of course - begs the question... Is the stock 914 2.0L plenum a good starting point to modify to allow for the Ford TB?

Here are some pics for reference... I had a Bus 2.0L intake system to borrow, so I am basing my measurements and ideas off of that.

http://www.qtm.net/~persot/MS/

Any ideas, suggestions, etc, are appreciated!

Thanks,
Tom

[Tom Perso]

Lots of good replies - thanks!

I have seen Shad's plenum in person - he built it out of fiberglass and it seemed to work pretty good. If I were to build one, I would use mild sheet steel and weld it together. I might pick Shad's brain and see what he says.

Dave - thanks for the advice. I am thinking that the 2.0L plenum might be the way to go... I think adapting a domestic TB to it would be pretty easy.

Jake, you have an interesting point about the lobe center. I've noticed that I never have a lot of vaccum at idle when I T'd the vac connections on the 44's. I never thought much about it though.

Is the fact that there is little vac. at idle, so that is what makes it difficult to tune, or is it a vac. pulse (non-steady reading) at idle that makes it hard to tune?

Thanks
Tom