The Stovebolt Site Forums The Shop Area Engine Shop GMC 302 Carburetion

I'm in the process of deciding on the carb set-up for my 302 that will go in my '52 Chevy 1-ton. I have the original manifold that fits the stock Holley AA-1 and a mil. manifold that has small 4-bolt pattern. I have split exhaust and eventually plan to run a Clark 280VO (0.8 OD) driving a 4.11/4.10 rear end. This mean I'll never be running the engine up higher than about 3600 rpm. The engine is stock except the cam is a Performance 254S grind from Delta Camshaft. I'm looking for reasonably good fuel efficiency without losing low-end torque and hauling capacity. The options I've been considering are:
1. Stock AA-1.
2. Dual AA-1s with one set up as a mechanical-progressive secondary.
3. Progressive two-barrel; Carter/Weber or Holley/Weber.
4. A small 4-barrel with smallish primaries and bigger secondaries.

I would appreciate comments on the pro's and con's these options as well as on vacuum vs mechanical-progressive secondaries. On-line guides seem to agree that vacuum secondaries are best for automatic transmissions, but that's not an issue here.

Thanks

Vacuum secondaries are usually better for economy, they don't dump as big of a fuel load when you hit the throttle.

Carb choice can be a nightmare. A 500 4 bbl seems to be a popular choice for the big sixes, but it is a little too big. I would lean toward dual carbs. A friend has dual Holley/Webers on his 261 that he built for performance. They really woke up the engine. Has good bottom end now, and has had it up to 6,000 rpm doing burnouts! Lots of power.

For some good advice on carbs, search this forum for posts by carbking, he's very knowledgable and does carb restoration for a living. He doesn't post here much anymore, but you can learn a lot from what he has written.