[78 nova]

What a shock! This is JAYBOY. I haven't been on here in many years only to find out that a thread that I started 7 years ago s at the top! I had to change my name old info long gone. What I did then was to look under trucks n the parking lot with the owners permission and write down the 3 digit spring code that I found under the truck and what kind of truck it was. ( 2 or 4 wd 6 or v8 extended or swb). Also the year. Basically there were 3 "waves" of springs based on the year of the truck. Let me do some digging I think I have the info still written down. Jay

 

[78 nova]

Ok I found my old info and will gladly share it. These are rear springs. They came in what I would call "waves" where the code letters and part numbers changed to no real reason. This is a lot of info so I will do it in several posts.
First wave 02-03 SWB lowest rate at the top:
P/N. Code. Superseded P/N
15097373. 15207737 YNM

15097374. YDJ. 15207738 YNP
15097375. YEU. 15207739 YNR
15097376. YEW. 15207740 YNS
15097377. YEX. 15207741 YNT
15097378,. YEY. 15058049 YDJ
Possibly used on some 04 trucks. Most of this info I got by actually crawling under people's trucks in store parking lots ( with their permission). There is not a lot of difference between adjacent numbers. A lot of trucks had 2 different numbers on the same truck. Mine included. Next the second wave SWB:
Part number. Code
15207736. YNN
15207737. YNM

15207738. YNP
15207739. YNR
15207740. YNS
15207741. YNT
15207742. YNU
See how the first wave supersedes to the second wave. I have no idea what is still available new. The third and final wave for SWB:
P/N. Code
15948006 YUS
15948007. YUU or YUT
15948008. YUX
15948009. YUY
15948010. YUZ
My own 2007 SWB 6 cylinder 2 wd truck came with YUX and YUY springs in the rear. I don't know what the rates for these springs are just lower or higher compared to each other. Hopefully this will help someone out. On my next post I will list LWB springs.

 

[78 nova]

Ok here are the LWB rear springs. They also came in "waves" First wave:
P/N. Code. Superseded p/N
15173963. YHS
15173964. YHT
15173965. YHU. 15207609 YNH
15173966. YHV. 15207610 YNJ or YNK
15173963 is the std LWB replacement spring, or at least was at the time. Now for the second wave, some are superseded by parts in the first wave.
P/N. Code. Rate. Superseded P/N
15167578. YHH. 34.4. 15173963
15167579. YHK. 36.8. 15173964
15167580. YHL 39.3. 15207609 YNH
15167581. YHM. 41.9. 15207610.YNJ YNK
The last 2 springs in this wave is what I put on my truck. They came from an 05 LWB V8 4WD truck. They raised the back of my truck 7/8 of an inch. Surprisingly the ride was not much firmer, where these springs really shined is when the boat is hooked up. About 3 inches less sag in the rear. Now for the final wave:
P/N. Code. Rate
15207607. YND/ YNE?
15207608. YNF. 33.9
15207609. YNH. 36.2
15207610. YNJ/ YNK
This is all that I have. Most of this is 7 or so years old so a lot of parts aren't available any more. Like I said most of the information came off of trucks that I found on the street at the time.