it is great i cant say just how the spring its self because when i pull a pump down i cant help but mess with lots of other things inside it

the one and only disadvantage i can see if you dont have a good ear and a motor built to handle the RPMS then a nice little gift will fly through the side ask me how i know

i like the extra RPM when you need just a little bit more you got it

for the normal everyday driver i would go with the 3200-3600 range

for the guy that wants street and strip the 4K with HD rods cam springs retainers and luck
its awesome we got a 24V to spin 4753 once for about 10 seconds no idea how but oh man it was wild i will never forget the sound imagine a 15K RPM street bike sound but diesel

 

, i noticed a huge throtle response difference from my stock spring to my 3200 spring, the only reason i want the 4k gov spring is for even more throtle response, i dont feel my pump will fuel remotley close to that high of an rpm and its very hard on stuff, when drag racing season comes back around ill prob shift it at no more then 2800 it seems to not have any more power at that rpm so throttle response is my only desire, if its not a signifigant difference i dont really see the point????