540 BBC-what spark plugs
#22
Registered
I like the Autolite due to the shorter strap and less chance for detonation and better spark exposure. I run the 3924's in my 524 with 10:1 compression with no issues on 93 octane. I have a big cam carbureted engine and I idle for hours down a river and I have no fouling issues. But I do have a multi-spark ignition. I also bought an otoscope from walmart so I can check the banding on the strap to make sure I had the right timing and heat range.
#23
if its an est with the square coil they are very hot but need a lot of power you probably need to add a relay i run a 540 on the rich side and never foul a plug but if it is weak you will
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SB (07-22-2020)
#25
#26
#28
Platinum Member
Platinum Member
Ive ran them with10-1 on 93 and at 8.4-1 on pump gas and at 13 psi boost with 93, one of my favorite "cheap" plugs, I actually LIKE the projected tip because they dont foul easy. I ran a set of 3923s in my 548 w prochgarger for 100 hours, pulled them out at 40 or 50 hours and they looked good enough to just put back in. LOTS of idling too, Smitty
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