Im throwin 452 ft. lbs. at it with a 428 and hasnt grenaded on me yet[u].<==== the key word is hanging there[/u]
Then let me say it again. A TH350 in stock form is wimpy when you mate it to an Olds 455. Especially if you're driving it on the street. A TH350 will live longer if you drag race it because all the hard shifts are upshifts and the sprag can handle it.
You back up 450+ (torque or horsepower) to TH350 and start yanking it down into second (such as might be needed for passing gear)from drive and that lil puppy will be toast quickly. Why spend the bucks to patch up (properly built) a TH350 thats gonna puke if you abuse it. The only reason the TH400 was invented was because the TH350 could not stand the abuse that was being dished out by the GM engineers.
I've had decent success with a TH350 and it's an okay transmission, I guess. But putting a TH350 in an application where it's gonna be tortured is like putting a Band-Aid on cancer, in my opinion. As long as the parts are available I switch to a TH400 everytime over rebuilding a TH350. Just my .02 worth.