Build thread - 3.08 to 3.42 front and rear gear change

DaveO9 said:

No turbos or superchargers for me - if I do anything it will be a 6.0 from a same-vintage 3/4T Silvy. I am interested in the Truck Norris cam though. I'd like to keep VVT - is there an option for that?

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Yes. Texas Speed makes some good VVT cams for these engines. That said, I deleted VVT when I did my cam upgrade on my 2012 and haven't missed it. I get to drive my stock 2007 with the L92 (has VVT) back-to-back with my cammed 2012 all the time, and the difference is really stark. I'm running the Cam Motion Stage 2 Truck Cam which was ground specifically for the 6.2 (3-bolt, no VVT), and it's so much more satisfying. The power is instant and strong, even at low RPMs.

Best I can tell from hours of reading, is that the VVT system was mainly put in for fuel economy reasons and it's only good for maybe 15 ft lbs down low in stock form. That said, those that have VVT on larger cams (which come with the penalty of needing a phaser limiter to avoid bending valves), seem glad they kept it. All I can say is I don't miss it. The 6.0 and 6.2 have the same 823 rectangular port heads - legendary.

Note that the Truck Norris and Cam Motion cam I mentioned both have very similar specs except for the LSA. The Cam Motion is 117 vs 107 for the Norris. That Norris will have a choppy idle as a result, which I found to be most unpleasant in daily driving. The surging at traffic lights got really annoying with my previous BTR stage 2 truck cam at 111 LSA (generally the lower the LSA, the more idle chop there will be).

swathdiver said:

Dan, you can't add the factory controller without taking your truck apart, replacing the wiring harness and a bunch of modules and of course the programming. It truly is "integrated".

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Even if mine has the factory wires for it?

The Tekonsha is installed and fully functional, just hasn't been used to tow yet... Wires were factory buttoned up and labeled under steering column... I bought the plug, soldered and sealed it on and P3 worked?

DaveO9 said:

Thanks for the kind words and encouragement!

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You're welcome, you earned 'em

DaveO9 said:

it took me two years to get through engine rebuild and complete front end rebuild in my '76 Corvette

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I have a 1980 with 53,116. Only thing not original is the radio...and two of them showed up 10mi from me 2weeks ago. Couldn't believe my eyes. Guy wanted $20 a piece lol

DaveO9 said:

I've been told not to do TC with the unknowns on the trans. So I'll probably do them together.

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me too and in my case I would say that is a law. Nov will be 3yrs since I first started experiencing TCC lockup, I have a LOT of time in research on the JMBX TC and it's assoc issues.. But if yours is performing that well, and you feel like you need more pull power, I wouldnt hesitate

DaveO9 said:

I am interested in the Truck Norris cam though. I'd like to keep VVT - is there an option for that?

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Truck Norris > VVT by wide margin, but needs tuned for optimal performance. Very good friend, Avionics Eng, always says "it takes more than one thing to bring down a plane" ... VVT is one of the culprits responsible for TCC lockup issues. But, yes there are VVT cams available Texas Speed and Mast are two I know, prob several more

DaveO9 said:

Bummer. Love doing things OEM when I can.

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OEM is item specific for me. OE brake control is far more aesthetically pleasing than aftermarket.. Tekonsha is better system, but eyesore.. One of top reasons I came over rom CAFCNA(Avalanche) was: unlike most automotive brand specific forums, the braintrusts here understand that auto engineers are kept in a box by the greed of the stakeholders. Which forces them to use inferior ____(options). Unfortunately, those same greedy dudes own a bunch of the aftermarket companies too lol(but not really funny). There's also many aftermarket items that don't perform as claimed, are inferior to OE, or are complete scams! I want to think EVERY part of every automobile is the best it could possibly be (because that's how it should be)....I now know better.. I also used to think wickedness only lived in the darkest corners of a basement somewhere....I now know better

Imho, (much like life) it comes down to ones own ability to discern what is good/beneficial and achieves the desired goal from what is/does not? ...and I agree.....it sure helps to have a resource like this one

5StarCustmSolutns said:

Even if mine has the factory wires for it?

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No you don't, not for the factory one. We all have the wires for an aftermarket one. A GMT900 truck originally equipped with the integrated trailer brake controller will have RPO JL1.

swathdiver said:

No you don't, not for the factory one. We all have the wires for an aftermarket one. A GMT900 truck originally equipped with the integrated trailer brake controller will have RPO JL1.

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10-4 that's a copy! ....and thanks for crushing my dream of an ergonomicallly correct aesthetically pleasing cabin


What you do with that gear pattern??

5StarCustmSolutns said:

I have a 1980 with 53,116. Only thing not original is the radio...and two of them showed up 10mi from me 2weeks ago. Couldn't believe my eyes. Guy wanted $20 a piece lol

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I've had my '76 for 23 years - July of 2001. Bought it just a few weeks before my (still) wife and I got married. I've done a lot to it over the years, including paint, but I brought it BACK to the original silver, matched to the paint code in the door jam. Block is original, but it's bored, and I have vortec heads on it from a late 90s truck. I still run a q-jet, but not the original one. Still have the original and plan to rebuild it with parts from Cliff's Hi-Perf some day. Great driver car, but not much more. Just there to have fun with. Oh, and my radio IS original. but I have a FM modulator installed inline with the antenna so I can plug my phone in or an MP3 player.

5StarCustmSolutns said:

10-4 that's a copy! ....and thanks for crushing my dream of an ergonomicallly correct aesthetically pleasing cabin


What you do with that gear pattern??

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Sorry man, but I would have felt worse if I saw you spending money on something that wouldn't work.

I've decided to send it. Still sitting on the work bench, waiting for the weather to cool off a bit and the rains to stop or slow down to get the axle dressed up with new brackets, brakes, etc.

swathdiver said:

Sorry man, but I would have felt worse if I saw you spending money on something that wouldn't work.

I've decided to send it. Still sitting on the work bench, waiting for the weather to cool off a bit and the rains to stop or slow down to get the axle dressed up with new brackets, brakes, etc.

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Send it! The way I understood it, if you cant hit dead center on drive side, you're better to be a few hundred thou more toe than heel. IF there's wear over time it's more likely to be drive than coast which will, in effect, move the ring away from the pinion a couple 0.00001's(not much), which is what one would do in yours if they had a magic wand...

Sorry I don't have the photos of mine yet to share...

I've spent virtually all my spare time in the last few months:

Prepping for my 6L80 tear down and rebuild. It was pretty rough goin early... Then I finally reached out to the first man I ever saw use HP Tuners to breakdown the way GM has the TCC slip rate %'s setup, and show how he corrects the issue....Mr Hiram Gutierrez. Didn't hear back for a couple months... Then bang....he replied, sent me both GM build and tech manuals, advised about concerns, etc.. We've become modern day penpals since lol

Learning as much as I could get builders to explain to me about torque converters...

Then 62 days ago stumbled onto Backroads of Appalachia and the 24hr Rally events and have been flat buried in off road suspension geometry since... Kingpin angles and scrub radius as pertains to off-road (totally different than on road!) , 3-links, 4-links, triangulated 4-links, SAS, leaf packs, inverted leaf packs, coil/shock, full air, rebuilding high end off-road coilovers and shocks, the pro's and cons of the different styles of lifts, what actually is the most beneficial for clearance/wheel travel/articulation/durability/etc, long travel vs mid travel, wheel size, tire size....you name it!

....and to be honest: This suspension stuff and deciding how I'm going to maximize my GMT900 platform for on /off/tow/performance has been the coolest most intriguing research Ive ever taken on