The common Chevy bearing register is 4-11/16". The SM465 is an oddball at 5-1/8, and I believe there's some wimpy trannys that are under the 4&11, but they won't interest us.
I want the same thing in my burb (half decent 5 speed), but the T5 is a bit wimpy for my liking, and the NV4500 is expensive, heavy and not as good as it was originally cracked up to be.
This site has a ton of good information:
http://www.novak-adapt.com/knowledge...on_gateway.htm
Anyway from all of the above, I'm planning on going with a TKO-500, but this is hardly a cheap option. I just can't see anything else that:
1) fits a standard bellhousing will no goofing around
2) can take the torque of a V8 (where a T5 falls down) especially when towing
3) has lots of shifter position options so that it's close to stock (also a T5 weak point)
4) has overdrive (otherwise I'd use another SM465; great tranny)
The flip side is at today's gas prices, the overdrive will eventually pay for itself, plus I figure the TKO will be good for the life of the rig assuming it's not abused.
As for the bell to tranny bolts, I wouldn't worry if you have to nut and bolt it (both holes clear, not tapped). The register centers the matchup, the bolts just take the torque and the bending, and a nut and bolt can certainly handle that (I'd use a nyloc nut).
Anybody have another good suggestion that makes me think I'm smoking drugs here?