The 442s are still priced less than the equivalent Chevelle SS, though the gap at the top (W30 vs LS6) has narrowed.
Do your homework first. There's no equivalent of Colvin or MacNeish for Oldsmobiles, but you can start with the Olds FAQ, which is mirrored at 442.com but lives at
http://oldsjunction.classicoldsmobile.com/oldsfaq/ Beyond the serial number to prove its a real 442, you'll need a build sheet or window sticker to authenticate the options - Olds factory records are just as lost as Chevrolet's.
Not sure how locked into a 70 442 you are, but if you've made the leap from Chevy and are concerned about authenticity, why not a Buick? 70s & 72s have bulletproof PHS-type docs available via the Sloan Museum. GSX prices have gone through the roof (partly organically, partly a function of the level of restoration that's been seen recently), but the GS455 and even Stage cars are a relative good value. If you go the Buick route, v8buick.com is the place to start.
Whatever route you go, good luck in the search.
