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Hi David, my Azalea Aviation manual indicates AC Delco plugs AC 44F with a plug gag of 0.035”. Your distributor point gap should be set at 0.029 when we and when it reaches 0.016 should be serviced. Fuel should only be 100LL. If you want more specs and a torque chart I’ll be happy to share with you via your email address.
To get a good answer you need to specify what conversion (William Wynne, Azelea, maybe this is a home-made conversion?) you are using and what type of ignition you have. The stronger the ignition the larger the plug gap is set. Magnetos (weak power of spark) use gaps around .016 - that would be most certified engines and some conversion engines. Coil and breaker point ignitions use around .035 gap (stronger power, can jump a bigger gap and make a more vigerous spark) while modern electronic ignitions use spark plug gaps as large as .060 (very powerful electrical charge so jumps a huge gap and makes a very potent spark).
Do you have a manual for your engine? If not you should get one.
Updated info- Using Denso plugs .030.
Of course you are right. I have an Azalea Aviation 120 HP Corvair conversion engine with points and electronic ignition running off of a dpdt selector switch and redundant coils for each ignition choice. The electronic ignition is a FAST XRi unit. Point gap is 0.019, static point timing is 10 degrees BTDC number one cylinder. Plugs are AC/Delco 44F with a 0.32 plug gap. Engine is carbonated with a 40mm Revmaster slide carb. The combination provides excellent performance. The distributor is supplied by Azalea and tested at full speed to ensure a 28-32 degree BTDC advance at 2600 rpm. This is the total advance eg. 32 total with 10 degrees static included in that total 32 degrees. Do not exceed 32 degrees on the engine or you will get damaging detonation and I recommend you only use 100 LL. How’s that?