I've been looking for a spring for my brand F truck and don't want to spend an arm and leg for springs. I was surprised to find that in some cases, PAC springs cost the same or less than generic springs! And they have a big enough selection that I was able to find several pretty interesting springs.

Another thing I noticed in the PAC catalog was some springs with pretty low spring rates. These lend themselves to breaking in the cam and lifters. For example, on my FM truck I need an installed height of 1.820 and the valve opens more than a half inch. I found a spring that was 95 lb on the seat and 211 lb at 0.512" lift. This should make cam breakin less stressful, although valve float will be at a pretty low rpm.

Another thing that I noticed is that Comp makes springs like the Isky 2005, which I need one of to complete the set. They are built to fit into the smallblock chevy head without machining, but widen out to 1.45" at the top. It allowed the racer to use a larger spring without machining the valve pockets. Well, what if we turned the spring upside down? Now it's a modern beehive spring. for our 3/8" stem valves, chevy pickup 350s from the '70s used regular sized springs with 3/8 stems. They should be inexpensive.