292's respond well to additional carburetion even without headers. Dual 2bls gives you better distribution but the 4bl is less messing around sychronizing adjustments. I think you will notice a significant difference even with the stock cam. If you go with the 2bls the Holley-Webers from Stovebolt Engine Co. are great. They're a 2 stage 2bl (like half a 4bl) so mileage is good and performance improved. They are also very reasonable. He sells rebuilt ones for $65 but you will need an adaptor and I think those are $15. I run a pair of them on my 261 with a little cam and they are a nice combination.

1964 Chevrolet C-20 Fleetside, Otis
1950 Chevy 1/2-Ton, Kirby
1950 Chevy 1/2-Ton Shortbed, Walter