C1 plug shield mount screws?

[Al C.]

What kind of head does the "193938 screw assembly"have? What markings and finish?
In the AIM (1958, sec.6, sh.12) it appears to be an integral "washer" head.
Does it have a self-locking feature also? Is it the same in all 4 locations?
... Al '58 #378 245hp

[Dale Pearman]

Re: C1 plug shield mount screws?

My GM Engineering Standards fastener data calls for a 1/4-20 x 7/16ths pan head slotted with external tooth star lock washer in a plain finish. Part # 193938. The steel was GM 280.

Dale.

[John M.]

Re: C1 plug shield mount screws?

Al, On my 60, the fastener was identical to the ones on the oil pan, no head marks, but the head was indented with a little raised ring arround the edge of the head. John