Opinions please
I like Holleys and run them on my more powerful motors. On a 273 that's stock except for dual exhaust, I think an Edelbrock 500 with electric choke would work better than either 600 carb you suggest. My 273 is long gone, but I have a 56 Plymouth with a 277 poly, factory power pack with four barrel and dual exhaust. I ran a 600 Holley on it for a while, but couple years ago switched to a 500 Edelbrock. Although I have not timed it, full throttle performance feels the same - no better and no worse - but the 500's throttle response is crisper. Plus the electric choke makes it a lot easier to start when the car has been sitting for a while.
I like Holleys and run them on my more powerful motors. On a 273 that's stock except for dual exhaust, I think an Edelbrock 500 with electric choke would work better than either 600 carb you suggest. My 273 is long gone, but I have a 56 Plymouth with a 277 poly, factory power pack with four barrel and dual exhaust. I ran a 600 Holley on it for a while, but couple years ago switched to a 500 Edelbrock. Although I have not timed it, full throttle performance feels the same - no better and no worse - but the 500's throttle response is crisper. Plus the electric choke makes it a lot easier to start when the car has been sitting for a while.