Coan 20320-2. 258mm core. Set up for a 455-475, 10.50 et, 34-3500 lb car, 4.10 gear. 3800 stall, would flash about 4000. Very efficient down track. $950 new. I swapped this converter out for a 9" ptc that was suppose to make it quicker but didn't.
Intake and 1965 shop manuals still for sale. I have a performer (Not rpm) intake, mild port clean up $175 Coan 11" street converter 20202. Used one summer in a street car. $150. Sold Coan 10" max performance converter with super sprag 20320. 4000 stall. Used about 50 runs. $350 1972 original Buick shop manual $50 Sold 1965 original Buick Riviera shop manual. $75 Pm your number and I can text pics if needed. All prices plus shipping or pick up in Cincinnati, Ohio