What size plug gap is everyone running on their 235 6 cyl w/elect ignition. Stock says 0.35 w/ points - heard people run from 0.45 - 0.60
Ditto what uglydog56 says,, although, you can experiment by going with .060, see how it runs, back it down if you lose top end or acceleration,, You didnt say what kind of ignition and coil.. that might play into it,, Pertronix or ? In the past I have run a 250 straight six with stock hei for 80K miles with bosch plats at .060.. I think the HEI is more powerful than a stock coil with pertronix, but, thru experimenting you will find the "sweet spot"
HEI works great at 60 thou, but you will have cold start problems and hot misses with a points ignition at >45 thousandths. The stock coil just doesn't have enough inductance to fire that broad of a gap reliably.
I am very interested in the thread. I dont mean to hijack the tread but I hae a 235 with Pertronix Points Coversion thing and a Flame Thower coil. If I understand this correctly I can open my spark plug gap to .045. What kind of improvement would someone exept from making this change?
on v8 s i have went to 060 on regular ign and it takes no more voltage to fire that gap, thats what my live old Sun scope tells me but look out when plugs get old and dirty I am running about .070 on a ve 8 with pertronix module and hot coil , but if you get deposits {oil} on a plug you can get a miss fire the large gap is great to ignite a lean mixture or you are spewing unburned hydrocarbons out the tailpipe just my opinions and some of a well know automotive instructor that i paid a lot of $$$ to learn some of thisbest money i ever spent
If you make the gap wider than the spark plug design was intended, the tip can wear unevenly. Look for the Z suffix with AC Delco spark plugs, which allows for a wider gap than .045 I gap my spark plugs at .042 and found no difference to a .045 setting, with a pertronix flamethrower coil and ignition.
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