Tonytales,
I remember some pictures of high pressure air bottles that could be fitted. They would power, I assume, a combuster starter such as fitted to many early DC-8 and B707.
I cannot vouch for the DC-8 but all the B707 series, Conway and PW, I was involved with had the single air bottle located rear of the left hand undercarriage bay.
This was used to start the No.3 engine air starter not combuster starter, cross bleed from there on..
Some B707 operators had a unit in the wheel well for re-charging the bottle.
TW