I have CSR reverse flow. Never again. May sell this one and take the hit. PITA. Doesn't purge air. Tried every trick I know. Raised the front end 3 feet in the air, pulled a vacuum on the system to maximize fill. Damn near lost a new engine due to cavitation. I finally installed a zerk fitting next to the pump motor, on top, to bleed air from the vane cavity. Works, buts makes a mess.

I also installed hollow bolts in the cylinder heads on the intake face LF and RR. Drilled through the bottom of the bolt hole into the coolant passage to bleed air from being trapped in the cylinder heads. Crazy how much air was trapped even after I got the coolant flowing. Makes an even bigger mess when bleeding.

CSR makes a quality product, or so it seams, but the reverse flow pump has issues....FWIW