MOPAROFFICIAL
Oogliboogli
Most lose 9-14 lbs after heat cycling in a running engine turning upwards of 65-7000rpm.My speedmaster springs have lost about 600 rpm before float. But I have a solid cam and shift at about 7000 rpm. That's about where they float now. Not saying springs are bad, just not for my combo.
Better the manufacturing..the less they lose. But most major brands 'Well known' and widely used stuff are light after 1000-1500 miles. Again why you spend the extra or CHECK and shim. . . Be it racing on a dollar or a dime...be smart.