I have a 1974 Chevy pickup with a 4 bolt main 350 built that I built for towing. 350 HP 430 lbs. of torque. Not giant numbers, but it tows our 2 horse trailer loaded with 2 hay burners without any problems. I also have a 24 foot bumper pull travel trailer that is 4700 lbs. that I use to camp. It pulls it fine, but I am worried that the transmission is the weak link.
The truck only has 58,000 original miles and came stock with a 9" tailshaft
TH350. My question is, can a TH350 be built as strong as a TH400? I know that a TH400 takes more power to run because they came behind big blocks a lot from the factory. Plus, it is kind of a pain to change it over to a TH400.