Technical 51 mercury front springs

bought a 51 merk in the trunk is a new pair of front springs have tag that says +30%-3 any body know what that means thank you

 

30% stiffer and 3" shorter compared to stock ones.Just guessing.Someone probably will know for sure.

 

I think that's how Jamco labels their springs.

 

Yes, our drop coils are manufactured with a 30% stiffer spring rate. Ours would be labeled +30% -3"