at what revs should i set my shift light on my 1.8 zetec, 136 cams, bike carbs, arp engine bolts. megajolt
cheers.

6500 RPM

You need a dyno read out to be 100% of the optimum shift point.

I had my 2L Zetec car up to 7200 on a fairly regular basis. As said though - there's not too much point going quite so high if the power is tailing off too much.

I will be setting up the programmable outputs from my Megajolt to show 3 stage rev lights at peak torque, peak BHP and engine rev limit, with Cosworth rods and V6 cast pistons the rev limit will be 4000 ft per second or just under 8000rpm