yes,I would go down to an 18" or 17" blade on that clutch.

I would even run a smaller direct drive fan if it moved it away from the rad hose.

IMHO,I have never noticed any difference in HP/performance/MPG on a daily driver/street duty engine running a direct drive fan.

mine is 18"-7 blade fan from the 78 amc hornet 258 6 cyl. might scratch one up at a local JY/U-Pull.

mid 80s model /6 dippy/aspen/volare should have the 18"-5 blade