Topic: Correct style of BF32 spark plugs

[21.04]

I have a few dozen NOS BF32 plugs and have noticed two variations:  one has 5 ribs towards the tip of the plugs and other have 3 ribs.  Attached is a photo of the two variations.  Both are Autolite plugs and have star logos.  Was there a version of these that were used on the assembly line for a July 1,66 projected build HP Conv with engine assembly of 2/9/66? 

[Bob Gaines]

I have a few dozen NOS BF32 plugs and have noticed two variations:  one has 5 ribs towards the tip of the plugs and other have 3 ribs.  Attached is a photo of the two variations.  Both are Autolite plugs and have star logos.  Was there a version of these that were used on the assembly line for a July 1,66 projected build HP Conv with engine assembly of 2/9/66?

3 rib is much earlier then 1965. You want the 5 rib for 65 and up.

[21.04]

Thanks Bob!