WHERE is it leaking from? Unless the throttle shaft is really sloppy and will not return to idle consistently, THEN replace it with either a newer Holley of an Edelbrock carb. NONE of them will be as inexpensive as they were 10 years ago.
Get a quality kit from Holley, the thick Holley base gasket as the OEM used, and rebuild it.
Granted, when the cars were new, the Holleys had a bad reputation of "leaking" and needing rebuilds every year or so, but from my own experiences, that is not the case any more. The only issue with the Holleys is that when the accel pump diaphram starts to seep, it seeps directly onto the intake manifold (in plain sight, usually, which also causes a gasoline smell under the hood). That issue has a fix of sorts in a "blue" accel pump diaphram. Supposed to be more resistant to ethanol fuels.
The 1850 Holley is a very BASIC, "fit-all" carburetor. Manual choke included! Not what you want as it can need some calibration changes to work as it should. As to the fuel line entrance, you should be able to transfer your existing float bowl to the new Holley. BUT, unless you want to fiddle with it, an 1850 is not desired.
To fit an AVS-2 Edelbrock carb, you'll need a throttle shaft adapter and transfer your existing carburetor throttle cable stud. You'll also need that same adapter with a new Holley to adapt the GM-style throttle arm to work with the Chrysler linkages. Not a big deal, but needed.
As for as the electric choke, all it needs is a wire going to it which gets power when the ignition key is on. Not a big deal to get wired-in, just have to know where to attach the wire to get power when desired. Instructions will come with the carburetor. Past that, probably a slight choke thermostat adjustment to get the choke open a bit sooner.
Now, for the approx $450.00 you'll end up spending for a new carburetor and the items to make it work, that same money can fund a quality rebuild and still have the factory hook-up items. Getting it back to how good it was when new.
As for the Holley 1850, that part number is what Ford used on all of their 4bbl V-8s in 1958. Starting in about the 1980s, Holley took that carburetor and "universalized" it for their "price leader" carburetor, which retailed for about $100.00 back then. Want an automatic choke? They had an add-on kit for that. Want it to fit a non-GM application? An adapter kit for Ford and one for Chrysler. With the universal fuel bowl, you'd need some rubber lines between the filter and the carburetor. Now, in present time, that formerly $100.00 carbureetor is much more money.
There's also the Holley Street Demo carburetor which will bolt to your intake manifold, too, but it looks like and is a copy of the Carter ThermoQuad 4bbls. It is supposed to be a good carburetor in how it acts and such. Still need the throttle/transmission linkage adapter and it has an electric choke. It probably is still the least expensive option.
Summit sells a Holley look-alike 4bbl which seems to be a combination of some improved Holley features and adds Ford-style annular primary throttle venturis (as the AVS-2 has). For somebody wanting what seems like an "improved Holley 4bbl", that might be the ticket. I've not heard about how it works, but it seems promising. Same adapter needed for the linkages and has an electric choke. No way to get around these things with a non-OEM replacement carburetor.
Holley MIGHT have some Chrysler OEM-replacement carburetors available for a similar model year B-b0dy 440, but I have not investigated that. They used to have more OEM-replacement carbs in prior years, but that selection has dwindled in more recent times. They were not cheap, but bolted right on.
One of them was the 1971 Dodge SuperBee 383 4160 series carburetor. In its earlier version, it was an OEM carb, but as things progressed, Holley "hot rodded" with dual inlet race fuel bowls, a slightly more generic fuel calibration, and an electric choke. All of the "good stuff" many customers might want for a 350-455 cid application. Then added the GM throttle linkage to it. In this case, you swap your existing float bowls and transfer tube to the new carb, install the throttle linkage adapter, hook up the choke wire, and should be done.
Holleys are NOT hard to rebuild. If it has "leaks", new gaskets and seals should take care of that. Those things will be in the carburetor kit. To me, the best way to go would be to rebuild what you have rather than get involved in adapting a new carburetor to your car. Same situation if you bought a core carburetor on eBay or similar, still need to get it rebuilt. Woodruff Carburetor, a member who advertises here, can be one of the best options for a rebuild, but you'll need to have the car unusable for a period of time while that rebuild is done.
Take care,
CBODY67
