Quote: Can anyone post good pics of 100% confirmed original 340 coil mount bolts? Looking for head markings and plating colors. Front and rear bolts may have been unique.
Glad you asked, because as I was getting ready to make photos, I discovered a few nifty factoids.
1. I posted in error above that one bolt had maker’s mark “GL” on the head. After looking more carefully at the actual bolt rather than my fastener spreadsheet, I now see that the maker’s mark is actually “E”. “E” maker’s mark is also found on the inside front cover here:
along with a list of finish codes, like S36 Zinc Dichromate (yellow - rainbow) on page 4.
2. The exact same bolt with maker’s mark “E” was used on the rear of my 69 340 R head for the head-to-firewall ground wire.
3. I think there are only three bolts 5/16-18 x 5/8 on my 69 Barracuda, the two on the coil mount and the one on the R head. Each is pictured below.
4. I say “I think” in factoid 3 above, because now I am on a mission to find the battery ground cable-to-L head, which is S36 finish and has engine blue paint on it. It may also be 5/16-18 x 5/8? This was one of the first bolts I removed in my restoration quest, and it may be (hopefully) the only one not found so far in my spreadsheet. Isn’t this fun?
BTW, my theory on why some S36 fasteners were found on the engine: these were specified for best electrical conductivity as in the case of the coil mount and the battery ground cable. The intake manifold had S36 bolts because the coil is mounted on it, but meantime the intake manifold has a gasket under it that is non-conductive.
Here is the coil mount bolt with maker’s mark “E” and with S36 zinc dichromate (yellow – rainbow) finish. The original dichromate is not visible because I have cleaned it for re-plating and re-chromating. This engine bolt was NOT painted engine blue; i.e., the coil was added after the painting.
