"... Not sure why people think they need a heavier rear like a 9" or Dana 60 with the massive 9.5" ring gear. That's overkill and over budget as far as I'm concerned..."
This statement makes me wanna know EXACTLY how much you think it will cost, to completely upgrade a 12-bolt, with bolt in axles(not C-clip elims), enuff to, without a doubt, withstand the abuse which a real healthy long stroke Pontiac can dish out.
Right off the bat, you'll need aftermarket tubes, with bolt-in axle type ends & matching brakes. Then you'll need a good quality posi & axles, new gears & bearings, and most guys will have to pay somebody to install & weld up the new tubes, as well as set up the posi & gears. Or, just buy the whole thing ready to bolt in, for which I've already posted links showing that a complete 12-bolt costs as much or more than a 9" Ford.
Also, I've read that the Dana 60 actually uses less power than the 9".
https://speedtalk.com/forum/viewtopic.php?f=19&t=28258
Now, if you just wanna try to piece together a cheap factory 12-bolt, with used parts & free labor, because of lack of budget, that's something different all together. I've had to do most of my racing the "poor boy" way.
Hey, a cheap homemade 12-bolt MIGHT be all that most will ever need. After buying an 11sec 455 Ventura, & running some 7.30's on our local 1/8 mile track, I discovered that it had an 8.2 rear. And not a BOP 8.2, but a Chevy 8.2.
I figured it had an original type 8.5, or a 12-bolt. Didn't think an 8.2 Chevy was supposed to live at that power level. But it DID !
Hey, there are lots of guys going pretty quick with the tiny 3rd & 4th gen Bird rears.
http://www.bangshift.com/forum/forum...-gm-7-5-handle
http://ls1tech.com/forums/drag-racin...5-10-bolt.html
http://www.hotrod.com/articles/hppp-...rearend-build/
So, this rear end deal is just like a lot of other performance parts. You can always read about SOME guys who have used the weaker parts and never broke 'em or had any problems at all. But, MOST others have not been that lucky.
So, except for the lack of finances, why even take a chance on questionable or borderline strength parts ? I'd say overkill is MUCH better, than taking a chance on all the bad things that a broke rear end can cause.