Header install question

Criminy, not many years ago, Every fall, I used to take my 367 out, and the trans, and the GVod and the rear pumpkin,
and swap in a 318/A904/different gears, no GVod; for the winter
in under two short days; drive it in/drive it out.
That Barracuda was my DD for six years until my son made me an offer on the 318/auto/3.55s that I just couldn't refuse; and I stuck it all into his truck.
That's what two days buys.

As for the TTIs, this is too easy;
put it on a 4-post hoist. Disconnect the battery.
Roll the travelling-jack under the K, jack it up until the wheels hang, then block it there. then roll the jack out.
Remove the T-bars, drop the steering, drop the starter.
Now you have a choice; drop the steering box or jack up the engine. I do the latter, but, remove the distributor cap first.
Install the driver's side header, from the top IIRC, by pushing the engine over to the passenger side as far as it goes. Boom down it goes. Drop the engine, and bolt her up.
Then off to the passenger side. Remove the oilfilter. This header goes in from either top or bottom.
In both cases, I leave the end studs in the heads, then hang the gaskets on them, then hang the headers on them, then just stick the nuts on a couple of turns., then just spin all the Allen socket screws in, etc. and secure the engine on the mounts.
Finally, I install the SHORT filter, then the starter then the T-bars, clearancing the headers as may be required, then the steering goes back in, and finally, reinstall the distributor cap .
Minus the clearancing, this doesn't take all morning.

I have a 4-speed, so the first time, I had MINOR clearance issues to both the Z-bar and the pushrod, so that took a bit of time to solve.
The first time, I used the big Mopar starter, which was a pain to work with. By the second time, the Dakota starter was in there, and it can stay on the engine during engine swap.
The first time, I had the 90* filter-adapter on the block. By the next time it was gone.
If you jack the engine up;
In my case the 7-Blade all steel fan will get into the rad, so one of them has to come out. The rad is easier, takes less time, and gives room to block the engine up under the balancer.
So, the first time, like somebody said, it can go to 6 hours. But if you make the changes I did, you could be down to 4.
Furthermore;
My record is 17 minutes to drop; the driveshaft, the front exhaust, the shifter, the GVod, and the aluminum bodied A833, yes 17 minutes., and no transmission jack was used..
At that point, with an engine lifter bolted onto the carb pad the engine can be out in just a few more minutes. Look; the trans is down, the rad is out, the engine is unbolted, the distributor cap is off, the manifolds are off, the starter is off;
the only things left are the wiring, the fuel system, maybe the bellhouse, and then the engine can go straight up and hang there.
At that point, with the engine UP and out of the way, you can just lay the headers on the aprons, retain them there with some tarp-straps, and drop the engine back down. The steering can stay and the T-bars too. Estimated time, IDK 5 hours total; start to finish. maybe 6 for the first time.
If you have an auto, it might take an additional 1 hour max total, depending how you go about it, I mean the trans does not have to actually come down, just unhooked from the engine, and since the T-bars can stay, I just use them to support the trans, leaving the shift mech and driveshaft installed. Only the cooler lines have to come off.
So using a car-hoist; no matter how you skin that cat, 5>6 hours is tops .

I have not done this job on the ground since I was 45, and at almost 71now, I don't want to. But if I had to, it would take me at least two hours to get everything prepped before I ever turned a wrench. I'm lifting the engine by chain-hoist under a big tree, and Ima jacking the car up high enough, so that I can roll my big self into position and not have to shimmy in there on my back on the grass. so then, the hood is coming off first.
I have taken a short cut by dropping the steering box, but I think it's not much faster, not much easier, and that stinking box seems unexpectedly heavy working in those confines, not to mention messy. Plus you know, getting under the dash to remove the steering column is not much fun either. But it does provide a ton of room, just not enough by itself.
I cannot afford to pay someone else to do this work, so I would have to do it myself, but I'd still have to hire somebody to stand around in a miniskirt to keep my spirits up; that somebody means my wife, and at 67, she ain't all that much inspiration anymore....... So then
I feel for you man, lol.