Hardware modifications GM style...

[1project2many]

Interesting.

For years I've wanted to build a two or three TB intake using the smaller 2bbl units found on 2.8 truck engines but I never thought about a dual bore unit like that. The smaller bore should be better for response and would be less likely to allow fuel to drop out of suspension provided you can tailor the AE curves correctly. I wonder if there's any advantage to swapping to late / big block injector pods and using pfi injectors with fuel pressure as high as possible to keep droplet size small?

[JeepsAndGuns]

Very interesting indeed. I'm intrested in how you connected the throttle linkage. Do you have it set up to where both shafts open at the same rate, or do you have it rigged up like a old 4v carb with mechanical seconairys.

[Six_Shooter]

Right now the throttle linkage just opens both throttle shafts together. Eventually, we might set it up to be progressive, but I will have to build a progressive injector controller to do that, to reduce possible flooding of the later opening throttle plates.

We plan to run it about 20 PSIG or so, at WOT, and use the vac ref FPR to bring fuel pressure down for idle. With the current TB, we could get it to either run like a scalded cat with high fuel pressure, or idle along, and have good manners at part throttle with lower pressure, but couldn't seem to get both.

BTW, it flows over 1100 CFM, dry flow flow.

[gregs78cam]

That's similar to what I had originally planned for my Camaro, but I decided to keep the linkage simple, and mounted them the same direction and real close.

[EagleMark]

Conjoined twins!

[gregs78cam]

Ya know you wouldn't have to make a injector controller if you set the main linkage to be progressive for both shafts. Know what I mean? Make the cable attach to the throttle lever only slightly ahead of the shaft centerline, instead of centering the arc of travel over the centerline. That way you have a slower opening at the beginning for better part throttle control, and faster opening at the end ...... progressive.

[Six_Shooter]

Ya know you wouldn't have to make a injector controller if you set the main linkage to be progressive for both shafts. Know what I mean? Make the cable attach to the throttle lever only slightly ahead of the shaft centerline, instead of centering the arc of travel over the centerline. That way you have a slower opening at the beginning for better part throttle control, and faster opening at the end ...... progressive.

Not that kind of progressive, the kind where the larger throttle plates stay closed until the smaller throttle plates are opened a certain amount at which point the larger throttle shafts open quickly. It does require the injectors to be progressive for the larger throttle plates, other wise the fuel puddles above those throttle plates and can cause stumble issues. It's been tried. ;)