fan spacer

[mluck]

i have the 20 inch 3 row radiator ..what size fan spacer do i use ..the one i have now measures 1 5/8 from the fan to the end of the spacer...using the 5 blade fan now...

 

[66Sprinter]

I recently upgraded from the 4 to a 6 blade flex fan...and I bought a 1.5" spacer...same setup as yours...

No farther than 2.25" and no closer than 1.5" is prolly a good yardstick