I have a 70 and a 73 164(and a 71-1800 with B20E). The b30 itself is pretty much the same as a b20 with only slightly less reliability as it's essentially the same motor but stretched with a few more parts. Having said that a slightly worn out b30 will probably still run okay for years. One of mine has never been opened. The cams can go on them, a few more valves to burn, etc. The fuel injection is essentially the same as the 142e so you know what to expect there. The mechanicals aren't really any more complex either. A touch more difficult to find parts for but not much. I have an auto in a 164 BW35 and really can't imagine how a b20 could get out of it's own way with the autobox...although I did have a 145 about 15 years ago with one. The B30E I have with approx 175hp isn't as quick or as fun as the B30A manual I have with what? 140hp? If you can live with that...If it's been kept up in good shape that will go a long way. If parts are hanging on with duct tape maybe give it a pass. Chances are good that whatever money you put into it you'll never see again. The B30 is a great motor in terms of reliability but you could partly say that Volvo built it's name/rep on the B20/18 in terms of reliabilty so it'd be a tall order to hold anything up to it imho. Service history? Condition now? Probably more important. A babied B30 could have ten good years left in it...etc.