Which kits in particular? I was planning on running the alumasports up front and the readispeed kit on the back with ss lines and hawk pads.

 

Is it the larger gears that suck power, or the full-float? Since I'll likely already have a 4L80E, I'm trying to keep SOME of the power I'll be making.

What horsepower level would you say a 9.5" gear setup is good to?

 

size of rotating mass robs power

 

I don't remember specifically, it was on another forum. But it was more than one instance. Whoever it was that was talking (more than one person) had dropped some serious $$$ and they were not very happy.

 

I wouldn't worry about a power robbing drivetrain, build it to last and run an extra pound of boost to make up for it. Driveline losses are a little over thought about for the most part, we drive street trucks, not race trucks.

 

I'm not thinking speed, I'm thinking efficiency. It looks like for the power I want to make that even a FLT Level 5 4L65E will be inadequate, so unless I hear good things in the next year about the 6L80/85E, I will be putting in a 4L80E, which means I will already be losing power in the transmission. I'd rather not lose any more power in the rear end than is necessary. If I can get a solid rear based upon a 9.5" ring gear, that's what I'll be doing.

 

I hear ya, but I think you should plan for durability first. Nice thing about the 10.5" 14bolt is they are strong as hell, cheap to build, plentiful, and a 6 lug conversion exists for them. You said Tahoe right, what does the 3/4 ton AV run for a rear diff setup? leaf or coils?

Bad thing about the 14 10.5" is they are heavy. worth it IMO

good luck

 

I am planning for durability, but no more than is necessary. I won't be towing 10,000 lbs so I don't need a 10,000 lb towing rear end.

Like I said before, if I can make a 9.5" ring gear rear end that does what I want it to do and will not break, that is what I will be going with.

 

the 9.5 will be plenty strong for your plans and is a good choice as well, might cost a bit more but who knows, in year there may be a drop in kit available if there isn't one already

 

The Bear folks are idiots... They will try to tell you that every axle from a non-HD truck takes the same Bear kit... despite the fact that the caliper anchors come in 2 distinct varieties (1 is ~4.5" and one is ~7.75" center bolt hole to center bolt hole). They also told me that they don't have dimensions for their kits available and don't know which variety it fits, because, you guessed it, there is only one size from GM... When I pointed out that I was measuring two calipers from 03, one from a SSS and one from a 1500 crew cab, he hung up. Wilwood is a bit better, but still has no solution if you want 6 lug.

I'd love to hear more about this relocation bracket that lets you use rotors from a 6 lug truck. Lemme tell you -- it ain't gonna happen. The hat is .45" too deep, so the rotor itself is the problem, not the caliper placement.

BTW, I had no trouble getting after market parts for the my 9.5. Brakes, yes, but gears, carriers, axles, even a TA girdle were readily available. Counting a brand new GM housing (which was $1100) I build a detroit locker with custom axles and micronited R&P for < $3k. Pretty comparable to the 12 bolt or ford 9" sets I saw.