W2 head installed valve spring height
I find that to be true pretty often for many new-in-box springs.
They’ll often fall back closer to “spec” after several high rpm blasts.
But not always.
I’ve had the heads come in for freshening after a couple of seasons and the springs still test higher than spec.
Especially with the old H11 springs, which would lose a bunch of load in short order.
My fav are cam grinders giving pressures theyd like to see used, then they have no actual spring part # recommendation.
I find a spring that ends up either lighter on seat than what they want and just right at the open...or higher seat and open than they want and definitely higher than I'd set them up at.
Old purple solid cams would run all day with 120seat and 300-open less sometimes..
Mp .557 and smaller ran with springs that were 120 and 275
By the time I pulled some 847 singles off that I used with a .528, the seat went from 120 to about 100 lbs and the open was down to 260 something iirr.
Wide margin before you break something.
Newer stuff works w/ 135-145seat and 305-315 by .500..but usually no more than about 330.
Spring pressures...what's ideal for street , is not adequate for strip ... and what's adequate for strip is too much for Street and ime a parts killer most everytime.
Anyone wanting to run on the high side spring pressure if they're breaking in the can better do it with the outer spring only or it will definitely wipe it out
