I assume you mean Ampex. If so, it's probably 456 or 457. The black, "rubberized" backcoating on those tapes will come off in sticky shreds and gunk up the tape path of any machine you play them on (depending a little bit on if you stored them in any kind of climate-controlled setting). There is a technique, originally described by Ampex themselves, to "restore" the tape enough to play at least one time. It doesn't always work, and you have to assume you'll only get one chance -- that is, one pass over the heads, so no foolin' around. Set your levels as quickly as you can and transfer to digital format on the first pass. If the tape hasn't completely fallen apart by then and you need another pass to get a better level, lucky you.
Here's one recipe for doing it yourself. I can't vouch for the validity of that link. It might work, it might not.
Here's a guy who says he can do it. I wouldn't want to try it myself if you can find someone who's pulled it off successfully.
I wish you the best, and I hope you'll come back and report on the results.