On a 85 305 TPI auto with usual low-cost mods, and STOCK CHIP, what have any of you found to be the best base timing setting for performance, assuming the use of 91-92 octane? I know specs call for 6*, I,ve been running 10*-12*. It feels fine, however I know that too much timing will make knock sensor kick in----and pull out timing, sometimes too much, resulting in power loss. Comments?

 

On my '86 305TPI I ran 8*,it would detonate at anything above,but I also had 185,000 miles on it.Lower it to 8* and if you don't notice a loss in power you should be ok.I would say though if you are not hearing the motor detonate where you have it you should be good.

 

Leave it at 6°, advancing it will not change the spark curve of the computer, just confuse it. All timing changes should be made inside the chip by custom programming.

 

I also own an 85 LB9/auto car. The last time I was at the track, I played around with my timing a little. I found that my car ran best at 9* advanced. I gained .2 sec in the 1/4 over 6*. I could also feel a difference in the way the car was responding overall. At 11* the computer started to take timing away from me and slowed me down in the quarter mile. I understand what John was saying...We should really burn our own proms so we can control the total timing, not just shift it up or down a few degrees. But hell, if it makes the car faster...

-peace