Having had 440's in and out of my GTX three times in the last few years (and I'm running the 4 speed!), if I may:
(This is a 2-man deal! Don't be an Ed, do it safely!)
1. Headers need to be in the car, laid over in the inner fenders (something behind them protecting the paint!)
and not connected to the rest of the exhaust.
2. It's perfectly fine to have the starter already installed, especially if it's a mini. Mine is a stock Dakota starter, which is
a bit larger than the mini starters out there. Fits fine. Heck, wired up is even better.
3. You are going to be laying the tailshaft of the transmission back at an OBSCENE angle in order to clear things and get
it under the firewall, hence the 2nd pair of hands. Slow going!
Go a bit, adjust things, protect things, go a little more. Be ready underneath with a "ride" for the tailshaft once it's
down there enough because it's going to head for the floor quickly once under the firewall.
I've used a creeper, a floor jack and a transmission jack for this.
Anything stout enough for the job will do, but this is a must.
4. Make sure your helper is still alive under the car and that the tailshaft housing is still riding on it's makeshift transport.
Once the engine/transmission is substantially clear of the firewall and radiator support, get that trans crossmember ready
to take the place of your tailshaft buggy.
Loosely get that thing started on the transmission and use a floor jack to get under it; raise it up to mate with the
car crossmember and get it started over that.
Once there, final cha-cha can commence between getting the trans crossmember bolt holes lined up and those for the
engine mounts.
It's like building a big ol' model kit. Protect the firewall and protect the humans.
The rest will become readily apparent.