I also agree with advancing the cam, 4 degrees ought to do it some good.

Mt old 66 dart I raced would go 2 tenths faster with no fan at all than with the clutch fan witch I thought I needed the biggest baddest fan so it was pretty big, 4 bolts was easy enough to test back to back, when I put in an electric fan it did not slow back down. I gained a couple tenths from low gears in the 904 but it was geared pretty high (2.94).