Cummins HD valve springs & PDR GSK. For the 1994-1998 12v 6BT & 8v 4BT engines. 4bt kit sold as a set of eight (8) HD valve springs & a 3000/4000gsk. 6bt set sold as a of twelve (12) HD valve springs & a 3000/4000gsk. If you want fueling to 4000rpm, install all GSK springs...if you want fueling to 3000rpm, leave the 2 smallest springs out of injection pump on install. The seat pressure on these HD valve springs is ~148lbs at the installed height of 1.950. At 400 lift, the spring pressure is ~192-195lbs. At 500 lift, the spring pressure is ~210lbs. If you plan on running a P7100 gov spring kit (GSK) or an exhaust brake, you will need HD valve springs.These heavy duty valve springs are required if you plan on running any application of 3000rpm to 3800rpm and/or upto 50psi of boost. Don't be fooled by people selling cheap GSK's and valve springs out there. A broken spring will take out an engine. Don't be fooled by people selling cheap GSK's and valve springs out there. A broken spring will take out an engine

• 3000/4000 rpm rev kit & 60lb Over stock valve springs
• Comes with springs for intake and exhaust valves
• For 1994-98 12v and 4bt 8v engines with inline inj pump
• Kit for fueling past stock 2600RPM...will allow fueling to 3000 or 4000rpm
• PDR Diesel GSK & Genuine Cummins HD Valve Springs

3000/4000 rpm rev kit & 60lb Over stock valve springsCummins & PDRdiesel