I am running a 928 motorsports s/c setup. 83 4.7L L jet

Currently I have the FMU vacuum line attached to one of the small ports at front of TB next to idle adjust screw.

I have the BOV vacuum line attached to the other small port at front of TB. (was originally capped off at factory)

I have the vacuum/boost gauge attached to the large vacuum port on front of intake phlenum (spell?).

Not convinced the small ports are consistant intake vacuum/pressure. Any suggestions for a better source for intake vacuum/pressure? They do not like being connected together using any sort of T fittings.

My question is : Do the two side by side ports at front of TB next to idle adjustment represent manifold vacuum or are they ported somewhere else??

 

I think most people run the vacuum off the plenum. Thats where I plan on running both the BOV and BEGI off of. You should be running the boost gauge off of the supplied AFM intake adapter. Drill a hole in the side of it and tap it. All the lines on the throttle body are plugged with the exception of the 2 distributer lines. This is what I plan on doing for L-jet.

 

My setup is a little different. I only have advance on distributer and it runs from one of the rear ports. I have a combination vacuum/boost gauge so placement before the AFM wont work. No vacuum with throttle plate closed. I could always tap another spot in phlenum but dont want to risk shavings into engine.

 

Bumpy Dumpy

 

I put my FMU and boost gauge vacuum lines on a T fitting with the FPR. The blow off valve is tied in with a T at the front fuel damper. Both work really well, however mine is an LH car. I think this can be done on the L jet too.