if you happen to not have room for a clutch fan....which is looks like you're very cramped for space...i know a guy using the flex a lite 7 blade flex fan on his 632 cube BBC(street car). He likes it plenty. the uneven spaced fan blades keeps it quieter than the typical flex. That might give you a little more cooling than what you have in there now. If there is room for a clutch fan setup, I always prefer it as a first choice.

here is that fan. it comes in 17 inch also

http://www.summitracing.com/parts/FLX-1817/