My LCF with the original 283, original fan with no clutch, and original radiator and shroud has zero trouble keeping the engine cool. I agree that a shroud will be the best option.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy