I shouldn't have said they are ALL the same. You basically have 3 options the 910s, beehives, and hypermax high rev. The hypermax spring are wayyy over priced also not to mention they require machining of the heads. Why would anyone want to use those when there are drop in springs that perform the same if not better. Your heads don't care the brand of spring that is installed just that it closes the valves when its supposed to and keeps them closed when supposed too.
People keep on saying that 910s are junk which is not true. They have there place depending on the rpm boost and back pressure that your motor will see. It is the installation errors that makes 910s give problems it is as simple as you need X amount of seat pressure that is achieved by a specific installed height for Y amount of boost or back pressure.
Lets take these swamps spring that are right at $700 for springs, locks, retainers, and seals. They are essentially beehives and could be bought from other sources as well.
Anyway they have a spring rate of 400lbs/in of travel and a spring pressure of
[email protected] installed height. Let's say that we have a pretty hot setup that is running around 60psi of boost and 80psi of back pressure. Take your valve which has a surface area of 2.19in2 multiply that by the boost and back pressure. That gives you a minimum seat pressure needed to keep that valve closed under those conditions which is 131.4lbs for intake valve and 175.2lbs for the exhaust. There a safe seat pressure would be about 180lbs. That your spring and which is
[email protected] then it will be
[email protected] which is sufficient and at stock can lift would be
[email protected] lift and
[email protected] lift with an aftermarket cam. That is about the limit that you want to go on the max lift pressure unless modifications in the lifters to prevent collapsing or using solid lifters.
Now I ask you why would you need anything more then that or want to complicate the process by needing machine work done to the heads?? Those springs will handle anything that a huei injected 7.3 can throw at it with no machine work required!!
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