Oh ok, thats what I originally thought but then when I saw he had two in his garage I was wondering if maybe It did just go right on.
I can't make it out in your picture, but there is a 7 digit number stamped on the carb. Let us know what it is and we can let you know what that carb is from.
I'm calling it a Cadillac carb from the throttle arm and the air cleaner tower. Second to last digit of the ID will be a 3. There's a chapter in my book dedicated to visual ID of Quadrajets.
704 is a 1970-75 carburetor 5 is 1975 2 is Federal 4bbl Quadrajet (As opposed to California) 3 is Cadillac 0 is Automatic Transmission
Some searching shows this part number common on the 500 cid Cadillac V8. The calibration on one of these would be way off for a 350 V8. Maybe you could sell it or trade toward a 350 Buick Quadrajet & 4V intake manifold. Devon
With jet & metering rod changes and possibly float level settings this carb could be made to work on a Buick 350 or 455.
I've put 455 carbs on 350s and they seem to idle better. Stock 350 carb idle circuits and restricted for emissions. A 455 carb lets it get all the fuels it wants idling.
Send the carb off to Ken at Everyday Performance. I bet he can make it work fine on your 350 after you put a TA 4 barrel aluminum intake on it.
For the greater part, any Q-Jet can work on anything, but may or may not be optimal. There are throttle arm /linkage considerations that need to be worked through, those can disqualify a carb and sometimes so much work is required that it may be better to start with an application with closer starting calibration. Buick 350 applications are pretty commonly available, and I've pickled up some great 77-79 cores on ebay for super cheap in the past.. find one of those and have it calibrated/rebuilt, that would be my suggestion.
The idle air bypass might need to be plugged, beyond that its pretty easy to close up the idle mixture screws as needed. The jets and rods will need changed for sure.
I would not recommend using it. If you have one of my books check out page 42 for a detailed explanation. It's going to be labor intensive to build and calibrated, plus that particular model was a one year only deal, and for good reason. They have fundamental issues that are difficult if not near impossible to overcome.......FWIW.......Cliff