OK. Since you need a long drawn out reason I wouldn't run a TCI converter.
Here you go.
In 94, I cot a converter for a 1971 D200, it was a cheapo saturday night special. I put it on my rebuilt transmission, and stuck a mild (ish) 318 in front of it. After a week of playing around, it started to slip, I thought it was my transmission, but the fluid was clean, so I carefully drove it until a could figure out WTF.
Then, one morning, it started leaking. I took it apart, and found all kinds of neat stuff in my filter, all from the converter. It seems, knowing a lot more now, than I did when I was 16, that when they made the "sat special" they just bent the fins on a stock converter, well, the fins broke, and I was out a new converter. TCI said send it to em, so, I paid for the shipping, and sent it to em. They told me it was abused. Yepper, I tell you, a 318 has TONS of torque..........in a 4:10 gear truck..........they gave me every story under the sun as to why they would not waranty it. I put the stock converter back in the truck, and know what? Even though the stall was lower, it took off better anyway.
In 95 I started working on a 74 318 power duster. port-o0sonic, stage3 X Heads, solid roller, forgies, trayed, chamfered, honed with a plate, balanced, restricted, you know the drill. I, for some reason, bought a super streetfighter. When I put the whole mess together, and stuffed it in the little A body, with traction bars, and took it to the strip, I had a stall of about 3500, and the car did mid 12's.........it was OK, but something was up, it SHOULD have gone faster......
Well, one day, I stomped the gas, and it went in nuetral. Yep, you guessed it, converter...............(This one day, was about 2000 miles) Something had completely broke free in there, so, what do I do? I chuck the 600$ TCI converter in the core bin at our local tranny supply and converter shop, and have them custom build me a converter.......1100 bucks......
Well, I put it in, damn, I had a slightly lower stall, that was more consistent in the upper RPM's, and gained, well, from like 12.80 average, to 11.60's, best time of 11.53....(first run, go figure)
TCI was forgotten, till my buddy ordered a "street fighter" tranny for his 66 440 power D100 short bed............
The 440 didn't lope, didn't make anymore than say 375HP, and 500 pounds of TQ, and guess what?
slippity doodah, in oh, I don't know, three weeks of him commuting in it?
Well, a converter I don't know much about, but a 727? We dug in one thursday night.
What I found, was a bunch of cheap, POS, chinese made clutches, seals, and bands, and a three pinion, yeah, three pinion, ALUMINUM planetary, in a so-called "race" transmission.
TCI said those are rated to hold up just fine. After all, it was the clutches that were burned out.........not the planetary..............
We robbed the guts out of a 727 from a 77 440 2x truck, (four pinion, steel, if I remember) and the thing still works, with a NAPA rebuild kit, and the valve body off the TCI, and that brings me into the next TCI gripe, and B+M too, shift kits, but hell, I gotta get back to work, my trucks running.