Geez... All this work with 122/1800 rear ends recently (see 122 forum), but I didn't get into the 544 at all.

My guess though... its a Dana/spicer 27 just like a 122 sedan. Take a look at the back of the differential cover. Then zoom in to about the 4 o'clock position, and look at the little flat part of casting immediately under the axle. After scraping and cleaning, you'll probably fine a "27" cast into that spot. Probably has 4.10 gears as stock...There should be a steel tag on one of the bottom cover bolts that will confirm this.

Which way do you want to go with the gears anyhow? I'm not sure what if anything is available in a lower set... but you could go with 4.56 gears from an automatic 122 sedan... '66 or earlier (B18 only). Actually, don't hold me to that automatic thing... I just found something that states they have the 4.10 gears too. Wagon gears won't work...they are different. As are all '67 or later Volvos.

But...a quick google search for something like "dana 27 gears" should turn some stuff up. They were common an many sorts of cars...including various Studebaker, Jeep, and others...

-Matt