Hey Frank! It's funny you should bring up the Crane vs. GM thing, as we've been discussing that very thing in regards to the LT-1 units. When you get some time, read through
THIS THREAD to get everyones thoughts on the subject.
My opinion, and I think Pete feels this way as well, is that the Crane unit and the GM unit are identical, in every way, shape, and form as the original units were, and are a VERY good performance cam. There's been a couple guys on the board put the Crane 143 and a GM 143 on cam doctors and they come out the same. I recommend the Crane unit as does Pete.
Order the the Crane unit from your dealer and you'll be more than happy. One small tip, though: MAKE SURE your engine builder breaks in the cam on the outer valve springs ONLY. If you don't think that's important, just ask JLerum!