A Autolite "AR23" and a Autolite 23 both cross reference to a champion RV9YC or AC delco R42TS
They should have the same reach and similar heat range. I find autolite burn a bit different than champions but they are close enough.
The only ACCEL products I'll buy and use are the shorty spark plugs for header clearance (when required) and the old shool high perf ignition points for a points distributor.
I think AC delco makes a shorty plug too for this but I don't know the number.
When using the ACCEL spark plugs be sure the screw on tip is on tight.
AR25 is 3full heat ranges hotter. Good for moms stock grocery getter, too hot for high perf WOT driving.
='s Champion RV15YC.
Pesky headers. You'd think by now they would have figured out how to make a header that fits a SBC.