green is an sp3, blue an sp4, red my 888. all on the same dyno. all have cam timing mods and tuning as required (888 with st4 exhaust and nothing else). a 92 851 with the 33/29 heads should make similar power to my 888 with a larger exhaust. i think there had been at least one other sp3/4 on this dyno and it made similar power to these two. i ran an sp5 on this dyno and it made 118 when it hit the limiter and was still climbing. so i don't believe the sp2/3/4 series were overly powerful based on these dyno runs and the ones i've ridden. happy to be proven wrong though.
best i got out of my 851 on this dyno was 95 ish from memory - st4 exhaust, cam timing changes, tuned and with less spark advance at the top end, which gave it a couple more hp like the 888 did.
