Those cup motors do not work well for drag racing. If you notice, you can find them on ebay pretty cheap, around 7g. There are guys who've tried to make them work in comp eliminator, in dragsters and altereds, and they have given up. They've tried different camshaft profiles, converters, etc, but the design just does not lend itself well to the drag strip. The reason you can buy them cheap is that they are for one application only.

It takes more than horsepower to drag race. Those motors have a real short stroke, short deck, and make no torque or mid range power. They make 800+ power at 8500 rpm, but you don't run a drag car 8500 rpm beginning to end. The torque and mid range is equally important.

It's just a matter of application. Those motors are built for what they do, and they do it well. They run wide open for long periods, and make good power. But, they do not lend themselves for drag racing.