[mdross1]

You most likely will never need the large input shaft top loader with small block car especially in a Cobra unless your running DOT slicks and fond of sidestepping the clutch near redline. Even then doubt very much you would ever hurt these top loaders.
These transmissions properly built and setup are one of the smoothest shifting you will ever find. Personally always used the Hurst Competition Plus shifters on all our muscle cars.
A 10.5" diaphragm clutch will work just fine set your car up for a clutch cable (personal preference over hydraulic)
We have a freshly rebuilt toploader if you cannot find one locally.