Bfg

What are the correct coolant hose clamps that were used from the factory on a 65 Cutlass?

Ozzie

Here is what the 1965 Olds parts book shows for group 1.166, Clamp, hose:

11/16" to 1-1/4" part number 573239
1-5/16" to 2-1/4" part number 573246
1-9/16" to 2-1/2" part number 573247
5/8" to 23/32" part number 578096
1/2" to 5/8" part number 584578

It does not show applications, hence they will include "A" & "B" bodies.

Junkman

Your car would have come from the factory with Wittek hose clamps on the larger hoses, and it might have had them on the smaller hoses also, or they might have been Corbin clamps. I am not familiar with exactly what GM installed on your particular car, but across all lines, the larger radiator hose clamps were Wuttek Hose Clamps.
This is a picture of the clamps, prior to installation. Some people call them tower clamps.

Bfg

Thanks for the reply, after I did some research I found that the double ring hose clamps were correct for radiator and by-pass hoses and the spring ring type was used on the heater hoses. The tower type clamps you show are for 71-72 years.