Though mine is track only I'll share what I know. I run the same Pac 1224 spring in at 1.950". 285/292/.471 lobe cam with 1.7 rockers. The lifters are Isky Red-Zone bushed. For the first 500 passes the lifter bushings were pretty loose .0025"-.003". Now they are just under .0015". It originally hurt one intake tappet at about 60 passes. Sent them all back to Isky. They repaired it for free. Said the rest were fine. That was 600 passes ago. It runs 5w25 JR 1 synthetic oil. It gets changed once a year. Roughly 100 passses. I keep a lash log book. Lash is checked at about 25 passes. Each valve is noted if it's loose or tight. Seldom are there more than 2 that have moved .001". Sometimes one will measure tight at one check. Than loose the next. But never has any of them had a consistant pattern of getting loose or tight for that matter. I can say until the lifter bushings were replaced the roller axle oil feed hole was about .045" below the bottom of the lifter bushing. This time we used longer bushings so the axle has constant pressure. Though it showed no ill effects from being run that way for 500 passes