valve spring dilema

[jet1]

I have an engine that with factory cam and factory valve springs works perfectly.
HR236/246 .648.648 110lsa. pac1518 313 rate behive installed at 1.880 with only 125lbs on the seat. There are no rocker arm,spring, valve, lifter issues. amazing for such low spring pressures.
I plan on getting the heads ported and using a larger camshaft. The lift will ermain teh same but the duration will go up. If I am running more duration does that not simulate a higher rpm for the spring at a given rpm over teh previous camshaft?

I don't want to go to spring that is fine for the cam change jsut to have it overload the rocker etc.

[twl]

Generally speaking, having the same lift but longer duration would be easier duty on the spring. However, depending on how much rpm increase you plan, it might need some attention. or maybe not.

[jet1]

actually in this case its more of a steady state engine rpm and I will be running teh same rpm. I am looking at moving the tq peak closer to my running rpm of 6000-6200

[twl]

actually in this case its more of a steady state engine rpm and I will be running teh same rpm. I am looking at moving the tq peak closer to my running rpm of 6000-6200

IMO, they can stay just as they are, and do just fine in that application.

[4sfed]

actually in this case its more of a steady state engine rpm and I will be running teh same rpm. I am looking at moving the tq peak closer to my running rpm of 6000-6200

IMO, they can stay just as they are, and do just fine in that application.

An aftermarket cam will likely have a more aggressive lift/closing rate and need a little more spring . . . even at the same RPM.

[wyrmrider]

some reason e're not asking the camgrinder?
as posted above cam have widely different accelerations even with similar specs
camking's inverse radius profiles come in different levels which require different springs
however his grinds tend go be easier on the valvetrain (at similar specs) than other grinders
why?
inorder to get similar specs with a flat flank cam you have to work it harder
inverse radius can give 4 degrees or more of "cushion" or "wiggle room"
more acceleration or-more revs- or easier on the valvetrain

[jet1]

Great info! I am probably just trying to learn. I know camking knows but I have always been the guy that has to understand why things happen not just that they do happen. Thanks guys.