B230 2.3 liter four. The engine that Volvo built for over 50 years in one form or another that powered everything from cars to boats to tractors. Irv Gordon's '66 P1800 with over 3 million miles has the older 1.8 liter version in it.
Congratulations. It takes a lot of work to get that many miles out of a car. Up here in Michigan that thing would have been a pile of rust waiting for a stiff wind to blow it away years ago with that many miles on it.
We've camped all over western Pennsylvania. Maybe we crossed that bridge when we came to it in my Ford Escort! My 2004 Dodge truck with "hey that's got a Hemi" lasted 70,000 miles and I babied it. They advertise as America's toughest and longest lasting trucks. As for rust, we spent the past 23 years in Florida and was surprised to see very few rusted out vehicles. Back in central Illinois with one of the mildest winters I can remember.......... I'll swear I see 2017 cars rusting along the rocker panels!