The one for a 68-70 B-body big block is the same as 71-up small block B-and E body. I will add some info from Brewers performance website. Hope this helps, Matt
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TS913 TORQUE SHAFT 1970-1 E-BODY, 1971-4 B-BODY BIG BLOCK Details
Torque Shaft, fits 1970-1971 E-body/1971-4 B-body big block applications with 10.5" bellhousing (can also be used in 1972-4 cars when converting to big block). (WILL NOT FIT WITH 11" CAST IRON OR LAKEWOOD BELLHOUSINGS!) 9" tube lenght, lower offset adjuster arm welded 3/4" from end of tube, uses our AK450 adjusting rod kit.
Price: $89.95
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TS914 TORQUE SHAFT 1966-70 B-BODY BIG BLOCK, 1970-74 E, 1971-4 B SMALL BLOCK Details
Torque Shaft, fits 1966-70 B-body big block, 1970-74 E-body & 1971-74 B-body small block applications. Also works in 1970 & later B/E-body cars when using earlier 11" cast iron or Lakewood bellhousings. 9" tube lenght, lower offset adjuster arm welded 1 1/4" from end of tube, uses our AK449 adjusting rod kit.
Price: $89.95