My '66 Bug needs a new tranny. I've been shopping around and have located a '71 Swing Axle unit. Now the research I've done indicates that the gear ratios didn't change from '67 to '72 (which is what I want. My stock '66 unit is a pain on the highway), but the charts I've seen didn't make any distinction between the IRS and Swing Axle units made after '67. Is there a difference in gear ratios with these Swinger units or are they just IRS units with swing axles. Could this have been from a \"Canadian Standard\" model. I believe they came with 1200 motors. Correct me if I'm wrong, please.