Ok this still needs some work and I believe I have mostly enough parts to build the one for the passenger side. I built this to fit a long tube header around the factory steering shaft. It has 1 5/8" primaries and a 2.5" collector I believe. The collector is not welded on. What you see is what you get. Anything else I can find is a bonus. I have many hours in this. $150 plus shipping.
I will admit it has been a while since I have seen this in the car. I made it hug up to the bottom of the car about as close to everything as I could while maintaining some air gap to try and keep the heat down (I was planning on putting a heat shield on the floor most likely). Here is a picture showing two of the primaries. I know it isn't a great view, but it shows something.
The primaries should be within an inch in length. That is part of the reason the rear the rear primary curls up and around, in addition to being able to curl it around the steering shaft.