Hi Bobby,
The shop manual says;
2.687 inches
Number of coils= 13
Diameter= .484 inches
I ordered a new one from Moss earlier this year but
did not install it because it was substantially shorter than
the factory spec.. I think it was around 2.4 or 2.5 inches long with the 13 coils.
My original spring was compressed and had apparently lost some of it's original temper, if it ever had any. I lengthened it to the spec of the shop manual and then installed it. I pulled it back out and checked the length again and found it it had compressed back to the exact same shorter length that I had started with. I guess it had developed a " memory " at the shorter length.
I took it back out again and this time stretched it 2.9 inches long, reinstalled it , pulled it back out to check it a 2nd time and to my amazement, it was now 2.68 inches long. The spring apparently had a " memory " of the original length of 2.687 inches as well as the shorter length.
Since It seemed to be staying at the correct length this time and my oil pressure improved 5 or 10 lbs or so I left the original spring installed and if I ever see lower oil pressure again, I will check the length on the spring again. If it ever goes back to the shorter length, I'll stretch the new Moss spring to the correct length and then try my hand at heat treating the spring to see if I can get it to stay at the correct length. So far the oil pressure is staying the same as after I stretched the original spring back to the correct length so I have left it alone.
Ed