Between an 11.0 and a 10.80 at the track?...................................A good valve job. Re-cut the Manley std. length valves that I took out of the Sportsman heads to put in another set of Bowtie heads I have and the valves only had 2 seasons on them. Well I am glad I decided to cut them last night and will every time I have the heads off from now on. Seems when you race and run these SBC to 7200 the valve train does need more attention than my BBC's do. Like my old race buddy used to say, the difference between winning and loosing is just a couple of thousands on the machine and on the lights.