Just to make it MORE fun....
Edelbrock also makes new "Q-jets"!
All these designs have strengths and weaknesses. More importantly, all have improved versions from the original. Holley itself has several upgraded versions as does Barry Grant. Edelbock, a slightly upgraded Carter AFB (which Edlebrock owns and ALSO makes new versions of), has finally come out with the AVS, which has adjustable secondaries.
I use Edlebrocks on nearly everything because they really require virtually no adjustment to work right out of the box. They are also much, much easier to fully set up without removing from the vehicle, dumping gas everywhere. AFB's are also super easy to completely rebuild.
Since they are not actually truly vacuum OR mechanically operated, but more are flow sensed through a weighted door on the venturi, they are far, far more tolerant of overcarburetion than the holley design. I have 750's on this mild 350, on a 318 Mopar and an a Caddy 501 - all function fine, which would not likely be the case with a Holley.
They virtually never leak fuel like Holleys can because the fuel is not contained in bolted on and gasketted side mounted fuel bowls. They do seem to be more likely to leak air though than Holleys, but this is subjective - I can't be CERTAIN of it,but I seem to have to take extra care to use new gaskets with no defects, etc.
AFB designs are also virtually unaffected by backfires which even a single one of can destroy and old Holley power valve. All the newer Holley designs have corrected this problem though, and parts can be put on original ones, so this is not that important.
Holleys seem to work better in turns and are less sensitve to fuel dirt and variances in fuel pressure than AFB's. They also seem more capable of being EXACTLY tuned to a particular set up and to work perfectly over the whole load and RPM range. Parts for Holleys are also super available. AFB parts you generally get from a catalog, but all the catalogs carry them. That means less to me as I am getting fed up with the "air refreshner, alternator and cheap blinger "accessory" type parts "houses" that seem so prevalent now.
All these designs work fine though, which the EFI boys and girls will always claim never can happen, since they've never DRIVEN a carbbed car. Be aware of used carbs of any make that may have subtle warpings of castings or throttle shafts. If you have lots of problems that old "good deal" carb could be at fault, not the design used.
