Just for reference you could buy a 200R-4 from a place like California Performance Transmission for $1699. All in you for TQ convertor, shipping and various other parts anf install you would be at around $2500. Still well under his quote. Plus you would have an overdrive gear. I'm not recommending CPT, but do know a couple people who have had success with them.
His $3500 suggests that he thinks there is more wrong with the car beyond the trans. That and the "well one thing leads to another" comment.
1968 400 Coupe, verdoro green, black vinyl top, auto
1969 GTO Judge coupe, Carousel Red, manual
1971 Trans Am, cameo white, auto
1970 Buick Skylark Custom Convertible 350-4(driver), Fire Red, white top, auto
1972 Buick GS Stage 1, Royal Blue, black vinyl top, auto
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