If the trans is original to the motor its a 700R4/4L60. That said it doesn't appear to have a TV cable, so its most likely a TH350/TH400.
For $250 I'm willing to bet neither work.
Yeah i agree with that bet as long as there good useable cores i couldn't care seller says they were running when pulled the engine used oil and trans was slipping im expecting rod knock or worse and anything used i would expect to rebuild.. But i havent made a choice as i have 2 other vehicles im looking at 94 s10 blazer and a 1999 s1 truck cpi and tbi engines