History Driveshaft loop

Does anyone know or remember when NHRA first started requiring driveshaft safety loops? Seems that Google has lost that info along the way.

 

1958 book does not have it, 1961 book does. 2" x 1/4" hoop.

I don't have 59-60 rule books to look at, sorry.

 

Close enough Jim. I was pretty sure they were required in 65. I am building a model and trying to be fairly accurate with the details.

 

btw I just found the link again. download the files while you can. I'll get 59 and 60 so I have them.

https://www.dropbox.com/sh/2006u57wp7sqpxt/AAC9WnRAsXqmyEgvaR8KYSowa

edit: 59 was the first year.

 

I still have my rule book from 1964, they were required at that time.

 

I was required to run one in '61.

 

Easy way for GM trans is Butlerperfomance