Ok... this sort of thing is my bag baby.
There are tons of good carburetors out there. You kinda can't go wrong with any of the above. Sizing is the absolute key.
Visit all of the CFM calculators you can find online and they will show you just how oversized people usually go. Your 302 at 5500 rpm and 80% VE will only consume about 380 cfm. That isn't to say that 600 or 670 is too big, its just a complete waste of money to go pay for the big carburetor when you don't need it. Most carburetors will tolerate being oversized as long as you properly tune them, but they absolutely can sacrifice velocity and torque. There have been hundreds of articles done by Car Craft, Hot Rod, Popular Hot Rodding, Super Chevy.... etc that all show how a properly sized carburetor is faster than an oversized one.
You have to remember that with EFI, you can feed it copious volumes of air and the fact that it isn't burdened with the extra mass of fuel, nor does it have the requirement of keeping the fuel suspended in it, you can have a 9" throttle body and 10 gallon plenum and it won't have as much effect on your powerband as a carburetor. With the fuel being introduced at or near the throttle body itself in a carb, the need for proper carb and intake choice is paramount for drivability and driving enjoyment.
Sure, if you compare a 390 cfm 2-bbl and an 850 cfm 4-bbl, the 850 might have 5 more hp at redline and WOT, but what happens to the velocity and torque when you stab the throttle at 1000 rpms and 30% of your fuel comes out of suspension? Keep in mind also, 2bbl carbs are measured at 3"Hg, while 4bbl carbs are measured at 1.5"Hg. If you compare actual mass flow of at 500cfm 2bbl versus a 500 cfm 4bbl, the 4-pot actually flows more mass than the 2-pot. CFMs do not always equal CFMs.
There are also huge misconceptions about vacuum secondary versus mechanical. Vacuum secondaries on most carbs use a vacuum pot to open the secondary throttle. The only thing this really does is affect the timing of the secondaries opening. They are tunable, but it's one more thing to worry about. Vac secondaries have their place just like mechanical. All of them need to be matched to the engine.
Holley makes great carbs, and most of the Holley-based tuners like quick fuel and avenger do great things with them. I don't appreciate the power valves and the gaskets below the fuel line. I also don't like the equally-sized primary/secondary layout of most Holleys. Trying to get a carburetor to transition from low load to high load with the primaries and secondaries being the same size causes metering things that have to be compensated for in most carbs. Spreadbore carbs were invented for the street for that reason. Keep the normal street driving in small primaries for high velocity and super-responsive throttle, and then give the big loads to bigger throttles where it's needed. The first 50% of the engine's load range can be supplied by much less flow area than the upper 50%.
Edelbrock makes shiny, galvanized-looking bricks that are a re-hash of a Carter air-door carburetor that dates back to the pre-war 40s. They have made significant upgrades, but they are mostly upgrades to a tired design. Not a fan. Easy to work with.. which is good, because they will need a lot of tuning on your part. They make kind of stabbed guesses at metering. They have an idle circuit with adjustment screws, but no feedback/heat flow. Then they have pretty good referenced primaries, then they have big, uninspired secondaries. This means you'll have A/F ratios that fall close enough to where you want them and can't tell the difference, but they are random stabs at being close.
If you want (in my opinion) the absolute best of the best, Rochester Qjet is the only answer. They are the single most accurately metering carb you can get. Period. I don't care how much money Quick Fuel puts into an old Holley design, they can't copy the metering accuracy of a Qjet. The other benefit of the Qjet is that they are the only truly flow-sensing design available. Edelbrock tried to do it in an old Carter design but failed miserably. It looks like it works, but it doesn't. If you set it up to actually work as a flow-sensing design, it runs pig rich. So Edelbrock kinda sat back, defaulted the springs to "whatever" and let them flop open at the slightest hint of flow.
The Qjet has a mechanical secondary throttle (on most models defeated by a lockout when the choke is still on) but a flow-sensing door above the venturi, and most have a vacuum brake on that door. Ultimately tuneable, and a truly flow-sensing secondary. Qjets only come in two CFMs... 750 and 800, and yet they were used on everything from Stage 1 Buick 455s and Caddy 500s, all the way down to a 125-hp wheezer 305 and even 3.8L and 4.3L V6s.... AND GM used them all the way up through 1989 when everyone else had to go EFI to comply with EPA long before that. A 750 cfm carb on a 4.3L V6? And it passed the new EPA regs as late as 1989? Yup. In fact, when GM replaced the Qjet with TBI in the trucks, they almost didn't get the trucks to market because the TBI was very difficult to get to pass. In the GM circle, one of the easiest ways to gain 5 hp and 3mpg on the 88-93 TBI trucks is to just swap to a Qjet. I happen to fish every summer for the last 40+ years with the guy who helped originate the Qjet, and was a lead engineer on the TBI. He apologizes profusely for the absolute fustercluck that is the TBI. It was rushed to production, poorly designed, and a nightmare to get it to pass. He remembers late nights trying to get them to work properly, and as a joke one of the guys filled a spray bottle with gasoline to prove that he could squirt fuel more accurately than the TBI. They were shocked when he could make it idle smoother than the ECM. In the end, they were able to create a TBI 350 that made a completely useless 180hp/245tq, returned 13 mpg, and barely met EPA guidelines.
Qjets came in multiple forms and were used on Dodge and Ford for a time under different names, so there are spreadbore intakes for Ford. Above all, do NOT use an adapter to put a spreadbore carb onto a squarebore intake. The primaries will have massive velocity drop as they go from tiny to huge, and the secondaries will have the opposite issue going from huge to tiny. Squarebore carb on a spreadbore intake is fine, although not ideal.
Also, don't get an electronic Qjet. E-jets (as some of us call them) used a PWM valve to alter primary mixture based on a basic O2 sensor. They aren't really able to convert to non-electric status without epoxy and drilling, so its just not worth it. I used to hoard 800cfm Qjets like nobody's business. At one time I had 2 dozen or more. I have forgotten more than most will ever know about them, but I could brush up and help you make a killer Qjet that will work beautifully and (with the exception of setting the choke on a cold morning) make you forget it doesn't have EFI.
We can talk intakes if you want as well.
TL,DR... Holley makes great power, but poorer velocity which can mean lower torque, slower throttle response, and lower MPG. There is a reason racers choose Holley. Great at WOT, very good at everything else. Edelbrock makes bricks of aluminum that attempt to mix boom-boom juice and "the airs" in a vaguely acceptable ratio that the spark plug is able to ignite it and they succeed if you tune the crap out of them. Qjet is a from-scratch, ground up design for street vehicles that excels at drivability, MPG, and still delivers all the performance because they made the only true carb that can be oversized but still sense flow and have the same level of accuracy on a 500" engine as it does on a 231" engine.
