Interesting setup. A hotcam and boost. I thought this cam has a 112 LSA which is not the best for boost? Unless you know something I don't know.

I would recommend a 4L80e if you can do it. I always had the impression that it would not fit under the Tahoe's ???

 

You will need a 9.5" 14-Bolt or a Ford 9" with Eaton Posi and a 4L80-E with a custom-built driveshaft. Do not attempt to modify the stock driveshaft - it is thin and it will fold up on you. Consider fully boxing and gussetting all rear end linkage parts and replacing rubber bushings with poly.

Tahoes are heavy and plenty of it is in the back. A Tahoe with a lot of power on 255 street tires puts as much toque on a rear end as a pickup does with full racing slicks.

Also, if this is for pursuit use, consider swapping out the vacuum brake boost with a hydroboost unit.

Small diameter tires provide many advantages - less stress on the drivetrain, better braking because brakes will get better leverage, and better handling by lowering center of gravity.

 

i still think a 14 bolt is overkill and the weight added = no bueno. ford 9" would be the ticket. driveshaft for sure is needed. how much power should the tahoe put to the rear wheels? 600'ish?

 

Well, I speak from experience. I know a guy with a 2000 (OBS) Tahoe that's making 700/700 at the crank with a big block and nitrous oxide. He's a got a 9.5" semi-float 14-bolt in it. His cover bolts walk themselves out and it starts leaking, then he has to tighten, fill, repeat. Walking bolts are caused by torque distortion in the housing. The 12-bolt is nowhere near as stout as a 9.5" 14-bolt. Look at the axle sizes, the bearings, the carrier, the housing, even the diameter of the pinion shaft. Sure the 12-bolt is lighter but this is a Tahoe we're talking about. A 10.5" 14-bolt is the only thing that barely holds up under mine and I'm about to buy a third set of bearings. Tahoes weight nearly six thousand pounds and with good traction, the rear will see every bit of it - don't skimp on a SUV rear end!

 

thanks guys, that all helps keep it coming. i'm hoping to be putting 550-600 on the ground

 

Id shy away from a a loose converter based on experience. Heat + heavy + demanding conditions + torque = one sad transmission.

You'll lose a bit of "off the line muscle" but your trans will love you for it.

 

that's kinda weird that the bolts are backing out. didn't put threadlock on em?

in my old 3/4 ton I had the 10.5" full floating 14 bolt. that's a bad ************ right there. I had the stock gears in it and we'd beat the crap out of it offroad. never had a single problem with it. i was putting probably around 350/400 to the wheels with the mods. btw, that truck weighed probably in the 6.5k range. dunno exactly the weight but 3/4 ton 4x4 w/454 excab isn't too light

if you got a good ford 9" with strong axles and a good housing you'd be good to go. it's worth spending the extra dollars to get a higher end diff that's lighter than a 14b if you're concerned about weight.

this is gonna be one sweet tahoe when it's done. especially if if looks stock

 

What's you budget? The sky is the limit around here so we need some info on what price range you're working within.

 

14 bolt rear retro fits easier and is strong as hell, I got one sitting in my garage along with a detroit locker just waiting for me to get off my lazy ***. 14 bolt gets my vote.

 

sky's not the limit on this one, i have about 15k to spend though