my 904 is a pretty basic build that a guy in MN did for my dad years back. Stock shafts, A1 front clutch spring pack, front drum cross-drilled for oil relief, shimmed/stock band servos, Griner trans brake I removed for the Pro Trans piece that was in the 727. It was the mainstay behind our iron head 360 (went 10.8's in Vegas). It's just been sitting around for many years and now that I have my dads race car I'm just changing some things to a direction I would have gone. We went 727 so it would be "set it and forget it" I'm in AZ, he was in SoDak... all was seemingly ok until I put the W8 mill in front of it and I seemed to find a lot of weird weak links with it. Dave and Darren at Protrans really helped me get things right with it, but even breaking the pump lugs was like a WTH moment. Upgraded with the TCS piece. That trans has finally been good for many passes, and I should have left well enough alone (have 2 nice converters for it), but in the interest in "hot rodding" I was buried in family life this spring so the car went back under the knife. 904 is in, but now without pitfalls. First I learned a starter won't clear with a R3 block, so I had to grind the block and starter for fitment. Went to bolt the trans up and found I had .040" pull up on the converter. That was when the distant memory of a "spacer" in between the block and trans crept back into my mind. My dad confirmed this with an "ohhh yeah!!!" LOL. The aluminum driveshaft I'd ordered from Inland 10mos earlier ended up too short.... sent it back and for a buck 80 they made it right. No complaints there.... stuff happens when doing things like that. I hope to have the car back out in October to see what new teething pains I've created....