Does anybody know if you have to ground the purple wire to set total timing at 28 on a thunderbolt V ign. or what the inital timing needs to be at to get a total of 28 deg.? This is on a 1995 310 with L29 heads xe262h cam and Edelbrock performer intake. Thanks

Total timing on a TB V is controlled by the ECM and knock sensor. You just set base timing.

Are you sure you don't have a TB IV on a 1995????

It is thunderbolt V because it has a knock sensor.So I set the initial at 8 deg.and rely on the knock sensor to control max timing.