The is a good article in Pratical Performance Car in january's editions. explains the basics and why you do it, how you do it and then moves on to adjustable cam pulleys.

i can scan it in after the copyright period is over.

just out of interest does anyone know what the max degree shift, advance, retard, on both exhaust and inlet is on a 6A13TT engine before you get Valve piston contact.

because it sound like this can be a good way to get free power, as long as you have a dyno to aid setup.