Whereas my beloved Vendetta succumbed to a tragic clutch explosion a month ago, I'm still fixing Volvos. My roommate owns a 1978 Volvo 245, he doesn't like jalopies, partly because he has no taste, but mostly because he has no mechanical aptitude. The simplest problem sends him into a tailspin, so he has me fix all his car's simple problems and complains about how the Volvo I found him on Craigslist for seven hundred dollars isn't nearly as reliable as I said it would be. I counter that the engine still runs as promised, but he says he wants a car that never has a failure ever. I say you have to spend a lot more than seven hundred dollars to get that and he tells me to get on with it and goes back inside.

After I fixed its last problem a month ago I refused to fix any more problems, I would provide only advice. Its temperature gauge stopped working and I told him where the thermometer was, how to test it, and where to get a new one. A month later its head gasket blew because the water pump started leaking and he didn't notice it overheating due to a thermometer he never fixed. Fantastic. However, he says he's so tired of driving cool, interesting cars that occasionally have small problems that he is buying a boring new car for an amount of money that no sane man would ever spend on anything. So, he says, if I fix it I can have it. Which is what brings me to my question.

What is the size of the bolts that hold the head on in a 1978 245 with a B21? They appear to be allan bolts, because the car is just that Swedish apparently.