Timing with headers and no cat

Hello,

New to forums so bear with me . I recently installed a 1995 5.7l TBI engine in a 1972 Blazer. Used headers no converters stock mufflers . Have major low end power problems. Set timing to 0 degrees. Ran terrible needed to advance timing at 15 degrees. Runs real strong but still have idle load up problems cold. Used 1989 wiring harness since I used a 350TH tranny. Still need to hook up VSS sensor. Any suggestions on timing.

Thanks.

Did you disconnect the EST wire (black with tan strip) when you set the timing? I have checked the timing after reconnecting the EST wire and it was at 20.

//2000CAYukon

yes I did disconnect the wire set timing to zero and ran terrible. I set timing until it ran and started the best then put light on it again.

Thanks

Have you played with the TPS voltage? 'Loading up' especially when cold could be something else.

No I have not. I suppose I could have many sensors that are "bad" but the sensors should not have an effect on timing could they?