[tucsonjwt]

It sounds like you have a lot of money invested in your high horsepower setup, so I can see why you would want a high cooling capacity radiator. If you just want to keep the engine cool then I would think a stock Spectra radiator would get the job done. You could always swap it out for a better one if it did not work. I am not sure if that Ram Jet requires a minimum temperature to operate properly like modern engines.