I know the cummins 60lb springs are out there, but I was told theyre not much more spring force.. just rated for an exhaust brake.
Ive seen some aftermarket ones out there somewhere that were shaped like a beehive and rated for a lot more spring force so you can turn faster revs or run a high-lift cam without worrying about valve float.
Anyone recall who makes them? and do they make them for the older 12v setups?
Im looking into a cam install soon so the springs are on my list

 

Springs are a must. especially if you plan on rinning the higher rpms. I run as high as 4600rpms when I race or sled pull. I would not go over 2800 or so with stock springs. just my thought

 

I have put the 60's on my 12v and there is a significant difference.If you do a search you should find some pics with the 60 next to the stock and you can see the difference. The performance heads I have seen Have the 60's on them. The stuff I have read says to put them on if you run the 4GSk kit. I put them on mine because I was hitting over 3,500 rpm with my 3GSK kit. I think the 60's would be fine.

 

PureDieselPower.com