Can you turn them around backwards like the 2x4 carbs were and run a modified factory linkage?   I know you're a Mopar guy, so just trying to lend some help, but the carbs on these factory setups were turned around backwards, with the choke horns to the rear and the linkage on the pass side.  The rear carb has the linkage attachment point closer to the centerline of the shaft, but I'm sure you could modify the linkage rod and make it 1:1 instead of progressive.

The factory turned them around since the primary float bowl on a 4160 carb won't clear the distributor. The secondary bowl clears since it only has the metering plate. Throttle bodies are much smaller than carbs but these throttle bodies include the injectors so they are bit bulkier. I've mocked it up now with the distributor and it is close. I think it is going to work but I need to do a full mock up with the block to make sure that the distributor clears the throttle body when bolted in place. Air only throttle bodies would easily clear but then we would need to weld on the bungs which is a task by itself.

Does anyone know what the center to center distance should be for this intake? I get slightly different measurements depending on where I measure it. I'm going to go with 8.600 center to center unless someone knows better. Usually the factory used fractions rather than decimal but I don't think it is 8.625 so perhaps they went with the round number on this dimension.

Did a mockup in the car. Looks like the easiest approach is to run the throttle bodies forward rather than backwards. I'll put the fuel rail on the passenger side and the linkage on the driver side. Most likely need to bend the factory throttle rod assembly to get it to line up correctly but that shouldn't be too big of a task. The throttle linkage itself will need to be fabricated.

Looks like a small hood scoop is required. Might be able to get by without a scoop but the hood would need to be modified to clear the air cleaner. Some of the ribs below the hood need to be modified for clearance. That kind of stuff is outside of my wheelhouse so it will need to go to a body shop.

Aren't there any serious bracket guys on this forum? Those guys break out the jets whenever the DA changes by a few hundred feet of elevation.......

Not sure what David Reher was talking about there, racers definitely change the tune between Seattle and Denver. Rule of thumb is one jet size per 1000 ft of change in DA although opinions vary. There is a DA formula that racers use for jet changes. A change in altitude will change DA if everything else stays the same but sometimes you get bailed out since the temperature usually drops as the elevation increases. FAST uses something they call load indexed speed density to solve this issue. Rather than just looking at the static fuel maps they compare the ratio of MAP to BARO to know what is actually going on. If you start at sea level at 101 kPa and drive up a mountain and now you are at 90 kPa you haven't changed position on the fuel map although a static fuel table would say you have. So what FAST does is re-reference the fuel table to say that since you are on a mountain 90 kPa is the new 101 and everything shifts in reference.

Should be able to make a custom log pretty easily.

Yeah I have a design ready to go to the shop. I started with an extra fuel rail I had left over from a previous conversion. Just need to do some drilling and tapping then send it out for anodizing and it should be ready to go.

I'm setting it up for the dyno at the moment so linkage needs to be on the driver side there. Not sure what will work best in the car, we'll have to deal with that when we get there. It is a 63 1/2 Galaxie with a 390 4bbl so we'll most likely use as much of the factory linkage as possible. I build linkage kits for a lot of dual carb applications so I'm thinking I'll be able to fabricate something that works but I might scout around for a factory setup to see if I can rob some parts from it.

The throttle linkage on the throttle bodies runs into the air cleaner so something needs to be trimmed. One problem with generic throttle bodies is the linkage tries to be all things to everybody.

I'm trying to come up with a clean solution for the fuel lines since this setup requires 4 inputs. I'm leaning towards a log manifold type design with AN fittings rather than hose barbs.

I'm in the process of putting together an EFI system for the 482 inch FE that I'm building for Car Craft. I'm going to use dual throttle bodies from FAST and then a FAST controller. I went with throttle body injection rather than port injection since I'm using a tunnel wedge intake and I didn't want to weld the bungs into that intake.

I think the throttle body approach will work just fine. We're going to run bank to bank and I bet the performance will be very close to what dual carbs will provide. Of course, EFI opens up the door to a ton of other benefits that are difficult if not impossible to accomplish with a carb and distributor. You can tune the fuel curve with a few keystrokes in EFI while tuning a fuel curve on a carb can require hours if not days of dyno work. And the ignition system can also be quickly tuned for start retard, high speed retard, vacuum advance, etc. If you have a distributor you have to buy a bunch of add on modules to get that stuff.

Data logging is another thing that comes with the higher end EFI systems as well as stuff like a digital dash. I just finished up a couple of days on the dyno with a big block Mopar engine where we tried different fuels, multiple ignition advance points, multiple AFR targets, etc. all in just a few hours of testing. There were three of us in the control room looking at screens and we could make changes and run a pull within just a few minutes. If you want to add or reduce timing by 1/2 degree you hit the key and it changes by that amount. No struggling with the distributor and timing light trying to figure out if you changed it by 1/2 degree or not. Same on the carb tuning. If you want to take 1/2 point of AFR out from peak torque to peak power you just enter the keystrokes. Try figuring out how to get a carb to lean out 1/2 point between peak torque and peak RPM! Very few carb guys in the country are capable of doing that and none of them can get it perfectly correct in 30 seconds!