it's a 544. I'm not sure of the year though. I have one , it's a 1963 and I think they made them for quite a few years. They were volvo's most popular car. The 444's look almost identical. The one I have, has the red block which is part of the b' series blocks. They were used in the p1800's as well. In those they were built with more horse's. Later, the same block was used in the 240's but they were outfitted with fuel injection and a few other upgrades. Hope that gives you some info.