Initial timing

So, still having a hard start. Swapped ECU to an OEM orange box. Have initial now set at around 17/18*.
Took for a 45 minute round trip in to town to get new Champion plugs RN14YC. Currently running Autolite 66's.
Anyway on the trip the car is still backfiring thru exhaust at cruise/part throttle. On acceleration no miss/stumble, it seems "fine".
Gonna change plugs and using the timing light I'll chk for spark on all 8.
Coil swap may be next. And pull distributor again to chk rating on vac adv arm.
Thanks all.

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