Also known as 60lb over stock HD Valve Springs or 60# over HD Valve Springs

These heavy duty exhaust valve springs are required if you plan on running any exhaust brake or higher than stock rpm and or higher boost. Completely safe spring pressures, even for stock running components.

The seat pressure on these springs is ~150 lbs at the installed height of 1.950 x 1.69 rocker ratio = 253.5 lbs

If you have a mechanical 4bt 3.9L and are going to install an exhaust brake or turn higher than normal rpm or run higher boost than stock, you don’t have strong enough valve springs to effectively hold the valves close.

Don’t be fooled by people selling cheap springs out there. A broken spring can take out an engine………..