We had the M113A1 with the diesel. If you ran them out of fuel it would shake and break the supercharger drive shaft which was a spindly little thing with larger splines on both ends. During repair you had to time the blower to the engine when you replaced the shaft or the thing would never run smoothly. The sides on ours didn't have the row of periscopes, just flat sided. Even though the aluminum hull was thick an AK47 hitting at a 90* angle would put a dimple on the inside. An RPG would go through it unless it hit at an angle. Then it would carve a splay out across the aluminum side that looked like a sunburst. If the laterals were set properly so the thing would track straight without much correction and the tracks weren't loose you could hit 45 mph on the paved portions of highway 1.We also had three of these with 106 recoilless rifles mounted on the rear deck. Troop H 17th Cav, light Armor Air Mobile Chuy Lai VN
during my illustrious Army days at Yuma Proving Grounds, one of my tasks was testing the M667 version the the APC which carried and fired Lance guided missiles. That weapon had nuclear warhead capability. Over 2000 M667s were eventually built though I do not believe any nuclear missiles were ever shot in anger.
FMC had a factory in Newark California that built the main section of the M113, which were then shipped out somewhere else to be completed. I can remember being stopped at railroad crossings in the area while a long train of flatbed cars loaded with unpainted M113s passed by.
Encountered some of these with gasoline engines in Idaho in '81 or '82. They belonged to either N.G. or Reserve outfits and I was tasked from Ft Riley to work with them. I remember it told that they had GM small blocks. Sounded awesome firing up. No way would I have wanted to go anywhere hot in one of them.