I just swaped the HD thermo clutch with 7 blade fan from my 85 SB to the 440 in the 88 truck.

just order a HD max cooling thermo clutch for a mid 80s dodge truck,I use an 86 3/4 ton for the counter jerk to key in.

for an upgrade in rad capacity the 86 3/4 ton has a rad thats the same size wide and bolts in but is 2-3 inches taller,has its on metal fan shroud.

the differance is one is thermocoupler and one is viscus fluid

you want the one with the spring coil on the front

I would up to a 7 blade fan on the 446 as well.