I TESTED FANS ON MY CAR ALL LAST SUMMER , FLEX, ELEC. CLUTCH TYPE , FIXED FACTORY , ALL WITH A SHROUD , ALL IN A SMALL 68 BARRACUDA ENGINE BAY , W/ A 440/505 WEDGE .WHICH IS FAIRLY HOT , SUPPOSEDLY 761 H.P. , BUT HASNT RUN LIKE IT SO FAR.
I tried 4 dif. elec. fan set ups , but not a contour type , big joke in my case . FIXED 7 BLADE FACTORY COOLED THE BEST , BUT SETTLED ON A 7 BLADE CLUTCH TYPE , THE FIXED FAN WAS ABOUT 7-8 DEGREES BETTER , THAN ANY , BUT ACCORDING TO AN "ENGINE MASTERS" TEST , COST ABOUT 20 H.P------------JFYI