first of all , find the spout connector, it's by your ignition module on the distributor. with the car running, hook up your timing light and see what degree it is at with the connector removed. mark your distributor and the lower intake incase you want to go back the settings you had before.
with a half inch wrench or the adapted wrench they sell at autozone so you can use it on a 3/8" ratchet, hold the distributor cap down while you loosen the bolt below the distributor that holds it to the block. do not remove it, just loosen it until you can turn the distributor.
you hook the timing light up to the spark plug wire on cylinder #1 (passenger side, closest to front of the car)
if i am not mistaken, turning clockwise advances the timing and counter retards it.
on your balancer you will see these Marks
ATDC <- BTDC->>>
10 | | | | 0 | | | | 10 | | | | 20
with degrees inbetween. each mark represents 2 degrees, so inbetween would be one degree (duh). You do not ever put it below the 0 (0-10 ATDC), it is always above 0 BTDC
you have to look at the pointer on the balancer carefully and because you are looking at it from an angle, adjust it to where you think it would be if you could see it looking straight down (parallax error).
Just keep turning the distributor until you reach the timing you want. A quick way to tell if you are really too high on the timing is to give it gas while you are under the hood with the spout connector back in and the distributor tightened. If you hear any sound of pinging you need to back off the timing. After you get to the timing that doesnt ping, take it for a drive and if it doesnt ping there also , esp at WOT, you found a winner. You have to play with it, see what the car likes.
89 GT Hatch: Custom M90 Supercharged w/ Ported Trickflow Trackheat Heads, Stage 1 cam, Streetheat lower / Sheet metal upper, Tweecer RT & PLX Wideband, 75mm TB, 1.6 Roller rockers, 3.73s, MSD 6a, Canton 7qt Pan+ Windage tray, 36LB Injectors, 200 amp Alternator, 75mm Pro-Mas MAF, 190lph fuel pump,Spec Stage 1 Clutch,SouthSide LCA's, Pro 5.0 Shifter, Steeda CC Plates / Springs, FMS Aluminum Driveshaft, New T5 w/ 2.95 first gear, Underdrive pullies, Zirgo 3300Cfm Elec. Fan, AFCO alum. radiator