9:10PM. I've got to call it quits for the evening, which means the time trial is over. I'll still post my progress as I make it. I'm close, but couldn't quite make it to crank the car.
Drive shaft is bolted in, carburetor, choke and throttle cables reattached. Heater back in. Made new hoses to go between the heater and the intake. Rest of hoses have been installed and the radiator is in. The radiator gave me a time wasting adventure. The last captive nut cross threaded. I spent probably two hours trying to get it freed and another nut and bolt put in. While under the car I discovered the muffler had separated from the long exhaust pipe. I'll have to take it off and find some way to flare it which means it has to come off the car. With temperatures dropping it's not going to happen tonight.
So the question is can this conversion be performed in 72 hours? I think it is possible. Unfortunately I didn't have all that I needed and spent a lot of time on things like modifying the transmission and getting the rear mount in after the engine/transmission was in the car. The other thing to consider is all the complications of pulling and refitting the original engine/transmission apply.
While you don't modify the bodywork of the car, you certainly make up for it in mods to the transmission. 6 places to grind down for clearance, the hole sawed out for the starter clearance, and the original bolt holes drilled out to accept the new bolts. The suggestion to use a Dremel 115 bit made a huge difference. If you're going to perform your own modifications be warned, the aluminum shavings make a terrible mess.
While the instructions supplied suggest trying to fit the bottom half of the rear mount with the engine/transmission in the car, I wouldn't attempt it again. That wasted a lot of time since I had to pull the engine back out and fit the mount. If I had it to do over again I'd put the assembly mostly in, bolt the rear mount in and wiggle it in.