" Make sure your actually buying a bop 350..."
You can use a Chevy TH350. Just takes a simple adapter plate. You can buy one or make one. I made one and used it with a PG & a TH350. My 455 broke both trans, but the plate worked great.
http://www.jegs.com/i/JEGS-Performan...60172/10002/-1
Or, if you really wanna build a heavy duty TH350, you can replace the bell with a JW Ultra Bell.
https://www.summitracing.com/parts/j...xoCmE4QAvD_BwE
http://www.jegs.com/i/J-W-Performanc...BoC-pAQAvD_BwE
"...A bit cleaner look under the hood without the 350 TV cable."
Can build to run without the cable. Lots of rebuilt performance TH350's come without the cable. I've read lots of back & forth about whether the kickdown cable controls line pressure, or is only for shifting to a lower gear, when you floor the pedal. I'll leave that discussion/argument for others. Some have reported great operation, for many years, without the cable.
http://nastyz28.com/threads/had-th35...le-hole.20499/
Even this Jegs basic rebuilt TH350 is built to run without the cable.
http://www.jegs.com/i/JEGS-Performan...60300/10002/-1