My car specs call for BF32 spark plugs. What are folks using as alternate plugs? My understanding is the BF32 have a lower heat range than the BF42. I see Autolite 45’s come up as replacements, are they ok to use? My engine (351W 4V M code) is stock with a 600 cfm carb.
Autolite 45 is a simular replacement for the original. If you are looking to “fine tune” your motor it would depend on your climate/ Sea level, fuel type used, and driving style. Trial and error. Plugs are divided into heat ranges. If you want fuel economy during the week and power on the weekend, changing plugs is sometimes needed along with carb adjustments. 45’s offer a compromise. Perfect for a starting point. IMHO
Mine also had the 600 Holley when I bought it. Leaked like a sieve, Bogged at WOT with lots of black smoke. Found an original calibration 4300. Much better. Still has the mechanical secondary bog, but much less. I take advantage of it to allow the transmission to downshift with less wear.