Late follow up - I've replaced the carburettor with a different one (a Weber 34ADM off an unleaded XF ute) and all the stumbling and rough running is gone. As per Ford's starting instructions you need to pump the throttle once (only once!) to release the choke mechanism, then you hit the key and away she goes. Idles smoothly, revs cleanly, and has no noticeable flat spots, though I'm certain the jetting could be improved (it's jetted for a 250 so it's bound to be rich).
I've also (today) fitted a sort of crankcase recirculation system - I grabbed a PCV valve off an XH ute and stuck it and its grommet where the draft tube used to be. Now instead of spewing crankcase gases into the atmosphere, it spews them into the air cleaner to be sucked into the engine and re-combusted. Sometime soon I intend to replace the coil with a higher voltage coil to take advantage of the HEI-style distributor cap. I've also found a high performance Bosch plug to suit the early six cylinder, model number DR9BPX, that has a platinum electrode for durability and a 1.1mm gap instead of 0.9mm. Once I've done that I'll enlist someone (probably an unsuspecting parent!) to commandeer the video camera from the passenger seat.
JEEPaul, sorry I took so long to reply - I haven't had much of a chance to scratch between University and living in a different state...! I've attached photos of my engine mounts for you. I'm certain they're not stock, or at least they're a very early iteration of stock mounts... I don't need the 90 degree oil filter adapter thingo that original Combat 6 Jeeps seem to require. (Also yes I know one needs replacing soon...!)
old yellow or the beast
1964 Jeep Kaiser CJ5
1965 Jeep Kaiser CJ5 combat 6
2014 Jeep JK Wrangler Unlimited
