1963 Oil Drain Bolt Head Marking

[Henry A.]

What is the correct head marking for a 63 300HP oil pan drain bolt.

The JM indicates a 3/4 inch "M" hex head bolt. A major parts supplier only lists a bolt that is larger and the head is marked by an "A" with a circle around it.

Thanks for your knowledge.

[Joe R.]

Re: 1963 Oil Drain Bolt Head Marking

Henry,

Most of the 63 drain pan bolts have been "AP" that I have seen however "AP" was only one of several suppliers for the C-2's. "TR" bolts have been used as well as the "A" bolts you mentioned on 63's.

JR

[John H.]

Re: 1963 Oil Drain Bolt Head Marking

The JM indicates a 3/4 inch "M" hex head bolt.

Henry -

The JG is wrong - the drain plug is 7/8" hex.

[Henry A.]

Re: 1963 Oil Drain Bolt Head Marking

Thanks Joe and John.

[Joe R.]

Re: 1963 Oil Drain Bolt Head Marking

JG wrong! No way! I got docked in 93 because my plug was not a 9/16"!!! It wuz one of those big ones. Reasoning was that it had been stripped out and somebody put in one of those big ones! Go figure!

JR

PS. Henry, go with one of those big ones! AP, A or TR will get you points. Not deducts! That is if they have revised the JG-finally!

[Wayne M.]

Re: 1963 Oil Drain Bolt Head Marking

Henry,

Most of the 63 drain pan bolts have been "AP" that I have seen however "AP" was only one of several suppliers for the C-2's. "TR" bolts have been used as well as the "A" bolts you mentioned on 63's. ..

Joe -- This 7/8" 'circle A' has a magnetic tip. Was that original for a C2-era ?



c

[Michael H.]

Re: 1963 Oil Drain Bolt Head Marking

Joe -- This 7/8" 'circle A' has a magnetic tip. Was that original for a C2-era ?



c

Wayne

I think the drain plug with the magnet was only used for big block. Possibly 65-67, or later?

I think older parts books show the two different numbers for small block and big block.