How much lift?
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
If the stock springs have many miles on them you need new ones to increase lift. They will probably measure OK, but fatigue will keep them from performing like they should. Valvesprings are cheap, no sense taking an unnecessary risk. Also, if you have an EFI engine measure the clearance between the valve spring retainer and valveguide. On mine they are very close. I think I measured a clearance of 0.460 on mine, which is just enough to safely run about 0.430 lift. Blueprint stock lift is 0.398, but this can vary by 0.020 or so from valve to valve.
