[Formulajones]

You won't regret the overdrive decision. The initial cost might sting at first but after you drive the car you'll wonder why it wasn't done sooner.

One thing I really like about 200's are the gear ratios. The 2.74 first gear will really help get that big car moving, and the .67 overdrive will work nice with 3.55's.
2100 rpm will be about 70 mph with a 27-ish tall tire.

A lot of builders shy away from the lockup converter on these types of TV cable transmissions mainly because of the way it's activated. Usually electric solenoid via vacuum switch or one of the two. Very hard to adjust them to engage exactly where you want, and behind an engine with a bumpy camshaft can cause chugging when engaged at an inopportune time. Some of the vacuum switches can be tweaked with a small adjustment screw but the range is very limited.

That's where the electronic control transmissions have an advantage, as that lockup feature can now be programmed via computer to engage and disengage anywhere you please.

Even with that said, looking at your current planned build, and I'm sure you already know this, but a ~434-ish engine with a 220/228 @ .050 cam on a 112 should idle pretty darn smooth and produce a ton of vacuum, so I wouldn't suspect chugging with a lockup converter to be an issue.