Maxi-flow filter pump? Personally, I wouldn't use one. The passages have too many sharp turns which lowers pressure. Are they 1/4" pipe thread or physically 1/4" diameter? If the passages measure 1/4" I.D. then I'm right that the passages are too small.
I recommend full-flowing your case, and using a pump cover with an out fitting, such as a Berg cast iron pressure-relief cover.
1/4" pipe thread has an outside diameter of just over 1/2", about 3/8" inside diameter of fittings, which is 50% larger than 1/4" lines. AN lines are rated in 1/16", so AN-6 is 6/16 or 3/8, AN-8 is 1/2", AN-10 is 5/8".
AN-3 is usually used for brake lines, AN-4 and 6 are used for fuel, and AN-8 and 10 are usually used for oil.
If your cooler is near the engine, I'd use AN-8(what I did on my Spyder). If you have a front-mounted cooler then I'd use AN-10 to alleviate the pressure loss.