What is the biggest spring we can put on our heads
..open/closed/on the seat.... with and without machine work done to the head....what would the limit before you hurt the lifter...i have R lifters....

who makes the best spring for our head...

thx

 

I can tell you that a comp 986 spring will fit with no machining, as will a crane 99893, where a 987 wont fit, so somewhere in that range is where you have to machine.

If you want to know the best spring for our head witout machining, your choices are limited, I might suggest the 99893 as it has the highest seat pressure open, and best spring rate I have seen for a spring that does not require machining.

A good spring with machining might be the comp 977, very high spring rate, high seat pressure open. There are proably hundreds of other very good springs out there that will fit with machining, just depends on how much you want to spend, and what your goals are. The 977 is one of the higher seat pressures you want to put on a HR setup, much higher than that and you will be replacing lifters more often.