I have a 66' f250 camper special with the stock 300 hooked to the stock 4 speed. It already has a remand carb on it, and I am thinking of putting a new one one. Any suggestions?? I am in the dark when it comes to carburetors. About the only thing I know about them, is if they are working DON'T TOUCH THEM.
I have looked on Holley's website, but am not sure what the expected RPM output is on the 300, so I was lost there too.
Any help would be great!

 

Contrary to popular belief, smaller is better. You want to keep good vacuum through the venturis to maximize driveability and economy.

Holley 0-7448 350cfm 2 barrel is a good choice, and will bolt directly on in place of the motorcraft 2100/2150. But if I remember right the early 240/300's had the smaller rochester carb base plate setup. Adapter plates are available if that is the case.

Holley 0-8007 390 cfm 4 barrel is a good choice also because it has vacuum secondaries. I had one of these on a 300 that I had put an old Offenhauser manifold on, and it ran excellent. I wish I had kept that manifold!

 

Probably a better place to do some digging: Ford Six Performance: The Web's Leading Resource for Ford Inline Six-Cylinder Engines and Cars!

 

The 300, like most inline sixes, had various 1bbs on them. On your '66 it was most likely an autolite 1101. If its been replaced its possible it now has a holley 1940 (the 1940 was the stock replacement carb). From about the late '60s on, the 300s had the carter YF till EFI in '87.
I'm not really familier with the 1940 (though it seem a little too complicated for a 1bbl), but I've used both the autolites & the carters & they are simple, easy carbs to rebuild & tune. The YF is probably your best choice as they are easy to find & quite cheap. You'll find them on any '70s 300 & might even be able to get one at the parts store. They also show up on ebay occasionally. There were many other applications for the YF, so make sure you can use it on a 300 first. The 1101 is a bit harder to find, though you'll find many of the slightly smaller 1100 used on the smaller sixes (170 & 200) & the 240.

If you're thinking of going for a 2bbl or 4bbl, you'll either need an adapter for the stock intake, or an after market intake. Both offenhauser & clifford make intakes that can be used with either 2 or 4bbl carbs. I'm using an offy "C" with an autolite 2150 2bbl & like the results. There are many other 2bbls. As for 4bbs, I've heard guys using the holley 390 on thier 300s & having good results.
In many ways, the 300 is kinda like a 351 with 2 less cylinders & so you cah figure that a carb for a stock 351 will work all right. Having said that though, keep in mind that an inline six is an entirely different animal when it comes to performance. One biggie is that you want to keep the rpms DOWN (not up, like a v-style engine), thats how these things produce torque. Hope this helps.
Edwin