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Discussion Starter #1
Well some of you may know ive been having issues with my tbss. Well i remember when i had it tore down doing the cam i had 7.375 push rods... that just doesnt seem right to me.

What would be the point behind that short push rod? Heads being milled? Which im pretty sure these have not been milled, being they are 68cc's...

Truck ran flawless(should have left it alone) now its a turd. it will not even spin a tire. The truck will load up and die before it does, even once boost comes on it wont. I figured it would be spinning like crazy. Ive taken a few of my buddies(one checking out the tune and owning a turbo silverado) he even says something is not right.

I did air it up to 10 psi and have no boost leaks there.(8psi wastegate.) im lost at this point. Im probably just over looking something simple. Anyone have some input??
 

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TrailblazerSS
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You are not going to mask the what you are talking about with a SC:2cents:

You need to look at other things IMHO.

Good luck I know it will be badass when it's done:coolthumb:
 

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Loading up and sputtering if its not rich could also be misfire relared. What is the AFR when its sputtering, and loading up. I would rule out tune, but as previously mentioned, verify pushrod length. If it is misfire, throw in a misfire histogram and what cyl or cyld (s) are misfiring and go from there. Could be cracked plug(s) that dont mess up til boost. Could be valve springs not strong enough, etc. Might want to take it in for diagnosis to someone that works on performance LS and see what they say. You can then fix the issue yourself or leave it there.
 

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So you changed cams?
I'd think if it's not milled it should be 7.4in.
If it's cam timing I'd think you'd have valves in the Pistons if it was advanced. If it's retarded it'd be now low end like you mentioned. I'd do a compression test if you have the stuff to do it.
If the compression seems low for your cr I'd look at the cam timing.
I don't think the pr's are the real problem unless it's noisy.
 

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He posted a video on fb. It seems noisy at the tail pipe
 
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Discussion Starter #7 (Edited)
I have a push rod length checker.... had a shit load of work come in today so couldn't mess with it like I planned. I was going to check it today... but I'm thinking it should have 7.4s in it also.

I know I won't have the low end and instant power like the tvs. But when I say turd... I'm talking like a dud. Even n/a this setup should be stout.

I don't think the push rods are my problem at all. But just seems like they are not right, the motors always had lots of valve train noise.

Almost seems like the trucks got a burnt valve, or broke spring maybe, Is there something in the tune that can be turned off to not let me see the miss fire? Because to it sounds/feels like a miss. It bucks and stumbles and a/f goes crazy while just cruising. But my scan tool and even the aero force guage will not show a miss
 

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Pull the valve covers off and check the springs.
 
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Discussion Starter #9
Going to try and do that today. Don't have much going on today haha
 

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Discussion Starter #11
Compression is good... 175 every hole. Hope to have a 5" coupler today so I can air the cold side up.

I'm pretty much leaning towards the cam just being wrong.
 

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6.2 silverao
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That engine was always pretty loud. You may want to swap valve springs anyways as I know he bought those heads used and believe he used the springs that were on them.

As little as I do know it sounds like pat may have specd the wrong cam and done a few things wrong in the tune to patch it.
 

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Discussion Starter #13
He didn't spec it, Matt did.

it was spec'd for a gto, ls2 370, 75-80mm turbo. Guy was going trough sometching and was selling the build. Well saw the cam new in box and bought it. I messaged Matt on here and he didn't say much.

Cam that was in my tbss was very nice spec'd by him...so when I saw this was spec'd for pretty much same set up, and by him. Instead of waiting to have one spec'd I bought it.
 

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If that's what Matt has it specd for it should work! May be a touch on the big side because a GTO is a little lighter but it should still make the same power
 

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Discussion Starter #15
Pretty much what I was thinking! Yes they are lighter and the duration is higher than what I probably should run.... But it should make the same power.

I've even thought about pulling my stall and having it bumped up to 3500-3600. But I don't want to throw money away if I don't need to do that. It bucks and kicks driving down Under light throttle, and sitting there idling it almost acts like it wants to die. A/f will lean the hell out and the go rich like its compensating for something.
 

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O2 sensors both still good?
 
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