I have a mostly stock '67 122S with a BW35 and a later B20, but other than that the drivetrain is original. If I read the information at this link [http://www.volvoamazonpictures.se/powertrain/powertrain.php] correctly, I believe I have a Dana/Spicer 30 rear end with a 4.1:1 ratio. My question is, since the Dana 30 is a fairly common axle, could a different ring and pinion be swapped in to provide a taller ratio for better freeway cruising? I understand it would make the car slower overall, but it's already a BW35 haha. And to answer the inevitable "why not ditch the BW35?" questions - it's just not an option. I need to stick with the stock transmission for the time being.

I was thinking about perhaps a 3.73:1. I used an online calculator that estimated this would drop RPMs by about 400 at 65 mph, all other things being equal. New ring and pinon sets seem to be less than $200.

Anyone done this? Thoughts?