I know there are tools made specifically for it, but I'm having a hard time figuring out which one I need.

 

I used a 9/16 box end wrench with the box over the end. The longer wrench the better. Possibly vice grips too.

 

I've seen that method used, but the spring tool is supposed to make it a lot easier to do.

 

I used a leather belt. I am sure the proper tool would make the job easier.

 

https://www.ebay.com/itm/254516621371
This is all I could find on eBay. Is this the tool I need?

 

I don't have a copy of the 1967 Oldsmobile Body Service Manual. The manual for 1965 specifies tool J-21412 to adjust the rear compartment torque rods. On page 2F-8 the manual provides a dimensional drawing (Fig. 2F10) from which the tool could be fabricated. It is different from the one shown in the eBay ad.

 

Safety glasses...cost of winshield of wifes car behind it & time shez goin to run to store / ask whats pokin through window ??