The 4782 is the center carb for the Direct Connection Super Stock carburetors and was rated 5 CFM higher than the OE center carb (355CFM v. 350). The ends were 4783s, were mechanically operated, and also had accelerator pumps ("OOOOH... you have a 750 double-pumper? Well I've got a 1,355 triple-pumper!"). All three would've had side-hung float bowls with driver's-side inlets as delivered. OE fuel lines are not happenin'.
Could you theoretically make it work? Yes, with a center-hung float bowl (passenger-side inlet) it should fit just like the 4791 would. The factory divorced choke would even work (the pull-off is identical). It does not have the long arm for the idle-stop solenoid, though. The metering block is unique to the carb. One advantage to the 4782 is that the idle mixture screws are on the metering block rather than the throttle body, so setting idle mixture is far less painful than on the 4791/4792.
Despite having both setups, I've never measured things like air bleeds/IFR/PVCRs between them to know what's truly different, although the DC carbs were generally intended for 440s.
I daily-drove a 440 with the DC carbs for a couple of years. I'd use them over the factory vacuum setup for anything other than a restoration, at least on a 440. A lot of others have echoed that sentiment. I sold that setup 25 years ago, but when I started putting together another 440 intake I specifically sought (and eventually found) the DC parts.
Value? That's a tough call. I paid $700 shipped for all three, but that was 4+ years ago before things got completely preposterous price-wise. If it's unmolested and in excellent shape, I'd guess $300-$400, though it might take awhile--the guy that wants it has to find it. If it's been altered, that drops considerably. The right float bowl is about 1,000 times harder to find than one for a factory Six Pack end carb. I have a spare with a center-hung bowl (off the back of a 4150?!) that I bought on a "Best Offer" auction for $135. Nobody else was biting. I didn't care about the bowl.
It doesn't sound like you're doing a platinum restoration (you mentioned it being a '71). My advice would be to try the 4782 with a borrowed float bowl (one from the front of any dual-inlet non-Dominator Holley 4V should work). If it doesn't work well, or if the factory-exact look is imperative to you, the 4792 (automatic center) is a lot easier to find--and less expensive--since it's never gone out of production. That's what I'm doing. My car's a '74. 99.99% of observers will never know the difference, and I seriously doubt I will in terms of driveability.
