I like the Power Rams from Dick Bennet, too. They have the largest diameter of all the velocity stacks I have. Some of my other ones can't clear the integral butterfly choke valves on some Walbro carbs. The Power Rams are also the least expensive I've found.

I've found that some of my side-mounted carb engines likes to spit fuel out the carb, and the VS really helps with that and gives a smoother transition.