Funny to me nobody asked how big the cam was or the car weight and gearing...or converter stall. Or header/collector/system size.... Seems like '101' questions people always seem to ask.....EXCEPT when the subject is 'single vs dual planes on street driven 500" max wedge motors....ain't that a coincidence?

The 337 should make more hp up top but right off the bat your 850 carb is probably too small. And if you're in a heavy car the additional grunt from a dual plane may do more for your ET than the extra hp up top. -1 how well ported are the heads? The limit of a ported 440-2D is about 355-360cfm and any 500" 2d on a 500" motor needs at least a 950-1000cfm carb on it to test before you blame the manifold running a big inch motor with a dual plane and an 850 is like running a victor 340 with a 600 vacuum secondary. And a lot of people would be AMAZED how much difference the ideal sized and perfectly calibrated carb makes on ANY combination.

Ron ( Firefighter ) and Old school's 572" tests were VERY telling because those big 572" motors really tax the intake tuners, even a max wedge port is under-sized for those cubes. Still the 2d did respectably, but even more so when you consider that a 572 is more than a whole extra cylinder compared to a 500.

If your over ~3700 pounds w/d AND your flash is less than around 4800 my $ is on a ported dual plane no matter what the peak HP is. And If your natural torque peak is over 4500 the single will do better....if you have the gearing to take advantage of it. Peak hp left 'on the table' don't really mean much with heavy cars with automatics, higher average torque means a whole lot more in terms of ET. Opinions vary though. Cars like Ron 383mans 493" car, IMO is right at the cusp of where a 337 might pay off. Ron's makes less power than yours but the car is lighter and a well cammed/geared car that run's 10.60's.

The mod man, I don't have an opinion on that one. I have 2 337's, one virgin and one ported, nice manifold and if my car was sub 3500 pounds I know I'd like it better...but only by a little I'm betting. I'd like Ron to test the 337 back to back with a 'proper' 1000cfm carb, I am willing to lend them to him for testing and possibly even meet him somewhere to settle the 'friendly' debate objectively. The 337 leads on the Dyno but it remains to be seen on the track where average torque generally rules the day.

More power once you reach a high rpm doesn't mean as much if it takes the car longer to get there. tuning on a dyno brake and tuning against a torque converter are often very different, also tractability and roll on part throttle torque are IMO every bit as important a consideration.