Chevy was a lot more conservatives on when they used a Saginaw more like about 200HP or more got you a Muncie or a Super T-10 after 73..
Likely a LOT more profit margin as well.
"After 73" there were almost NO American made cars with over 300HP. If they were, it was a very special, very limited edition, offer. The time after 1973 was the period of choking smog regulated cars, after the demise of Muncie.
Advertising and Marketing play a huge role in pushing more expensive items on unwary customers ("...
you'll need the paint protection option!"). Granted, maybe the standard issue Sag 4 speed wasn't the best transmission around, but it could certainly handle any so-called "high performance" wheezing 225 HP cars of the late 70's and the 80's. Of course, if you abused it, it would break, then you'd need a muncie. That said, I can;t imagine a late 70's or 80's car being powerful enough to blow any transmission, unless brutally abused.
Once again, it depends on your driving style, and what you use the car for. Even a 800+ HP car that is only slowly driven to the local Cruise Night lot once or twice a month, and then slowly back home to it's conditioned, dehumidified garage doesn't need 90% of what has been done to it. Folks can do whatever they please with their cars, but shouldn't look down on fellow enthusiasts in an effort to raise themselves higher.
We used to call it: "
Run what ya' brung". Those were the good old days.
Choose wisely grasshopper.