Been looking for a new intake and carb to replace my vaporizer setup. One thing I'm not sure of. If I get something like a NH Holley setup will I still be able to use my exhaust manifold. My exhaust system is in good shape and I'd hate to have to mess with it.
No, the exhaust manifold is integral with the vaporizer unit because it uses hot exhaust gasses drawn across a heating plate to vaporize the fuel. However, if you are worried about your exhaust pipe fitting a manifold with an NH for the carb, I don't you will have a problem. You may have to get a special linkage adapter for the carb if there's no hole in the block for the throttle rod.
Russ Potter at Potters Carburetor rebuilt a vaporizer for me a few years ago. After rebuild it was the best T carburetor I ever experienced. You might give that option a consideration. Probably is cheaper than the changeover.
Randy, Kevin is correct. the Holley and Simmons vaporizer intake and exhaust manifolds are a thing of their own. The exhaust pipe and nut and everything back is the same, but to change to a "regular" T intake and exhaust manifold, both the intake and exhaust manifolds must be changed with the carburetor. Also, the vaporizers had the carb throttle rod extending OVER the engine and connected to a lever on the steering column near the firewall as opposed to T's with regular carb setups where the throttle rod passed through a hole punched out between cylinders 2 and 3. If your (steering column) throttle rod does not have a lever, both high for a vaporizer and lower, for a regular carb, a new lever must be installed at the lower position for the rod going through the block.