I am looking at torque converters and I see different bolt patterns. What bolt pattern would my 68 Delta 88 have? It is a Th-400 behind a 455. I see 10.75" bolt circle, and some that say small bolt pattern and 10.75"/11.5" dual bolt circle.

 

here they are http://www.jegs.com/webapp/wcs/store...+3018329&Nty=0

 

I believe your flex plate could handle either. If you have a stock converter it's probably a 12" with 11.5" pattern. I replaced the stock converter in my car a 12" (TH400) with the 11.5" pattern with a 10" converter (3000 stall) with 10.75" pattern and it bolted to the flex plate.