Spark plug gap after installing pertronics

[Ed'sreddart]

Just installed a pertronics ignition in my 66 dart slant six. Some places say you should increase the spark plug gap to get a hotter longer spark.
Question????? Should i increase the gap and how much.

 

[RustyRatRod]

What did the Pertronix instructions say?

 

[bw68d100318]

I have Pertronix kits and coils on my '68 318, and my '70 383, both Sweptlines (lower compression). I run my gaps 0.040 instead of factory 0.035. I've heard that gaps that approach 0.050 cause a rough idle, but run fine as higher rpms. My idle is a little rough, it could be a contributing factor. Dunno. I get 10/16 mpg with the big block/727/3.54 hauling a trailer, and highway unloaded at 55 respectively. That's about 20% better than before the pertronix. The 318/NP435/3.75 gets 16-22, depending on how hard I drive it.

 

[VDART]

I ran my slant with .045 gap good idle & clean throttle, my 318 I believe I did the same , Lawrence

 

[GEO]

I have Pertronix kits and coils on my '68 318, and my '70 383, both Sweptlines (lower compression). I run my gaps 0.040 instead of factory 0.035. I've heard that gaps that approach 0.050 cause a rough idle, but run fine as higher rpms. My idle is a little rough, it could be a contributing factor. Dunno. I get 10/16 mpg with the big block/727/3.54 hauling a trailer, and highway unloaded at 55 respectively. That's about 20% better than before the pertronix. The 318/NP435/3.75 gets 16-22, depending on how hard I drive it.

I too bump mine up to .040 when putting in electronic ignition