I've shim many sets of Comp Cam valve springs to get between 145 to 175 lbs. on the seats as long as it doesn't exceed 375 lbs. open
I did one motor for 9secondphil that had a custom ground Comp Cams NASCAR grind that ended up with 435 lbs. opened with 160 lbs. on the seats, we remove the inner springs to break it in, which reduce right at 30 lbs. on the seats and close to 45 lbs. at max lift. He put a lot of hard miles on that engine on the street and at the tracks back east, spraying it as well as racing it N/A