2x4 intake

[Fuelie Fan]

It wouldn't be too hard.

Holley sells 4bbl throttle bodies without fuel rails, just an in and an out. You could plumb it one of two ways:
1. Allow each throttle body it's own regulator. You would tee the supply line, one to each throttle body, then tee the returns back together
2. Gut the regulator in the first throttle body, and run it in series.



Approach #2 was used by GM (Remember the Cross-Fire?!?!?), except I think they had a damper in the first throttle body. It's cleaner and less complicated, and probably all that's required.

With a 2 4bbl TBI's, you'd have 8 injectors, so you would size them pretty much exactly as if you were doing a MPFI setup. The smallest available TBI injector, to my knowledge, is 31 lb/hr, which would be perfect for around 400 hp. If you've got less, you may run in to idle instability. Doesn't seem like too many people on this website have less than that though. :0

Be sure to batch the injectors in a split fashion, ie pair two from one throttle body with two from the other. Otherwise you'll run into distribution problems.

Idle control could be an issue, since you'd only have an IAC on one of the two throttle bodies. I think a generous plenum size will cover this up, though. Shouldn't be a big deal.