What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[gooffeyguy]

Are your wires straight or have slack to be a little curved, like the red ones in my pic? There are so many variations for the truck wires that seem to have no real significance. I can see a difference in the LS9 wires versus the truck wires. But why would two Gen IV engines have different wires, ya know?

I actually kinda like them blue wires being pulled straight from an aesthetics standpoint.

My wires have ACDelco 5146 on them

 

[gooffeyguy]

I've never been able to understand why there are so many variants of OE wires.




I saw 748UU, 'CC, 'GG, 'HH, 'RR, 'VV and 'TT.

748UU looks to be straight boot and black. I'm sure this is what Tom has and likely yours (I'm assuming yours are black).

748CC looks to be the same as 'UU

748GG looks to be the same as 'UU.

748HH looks to be the same as 'UU, but a little longer

748RR has the 90° boot and are red, so I'd assume that's what my current ones are.

748VV are what I just bought, blue, straight boot but slightly shorter and are for the LS9

748TT looks to be the same as 'VV, but red.

The 748RR (your red 90*) shows as not fitting my vehicle when looking at them on Advance Auto's site. I like the 90* boots, gives a cleaner look I think

 

[89Suburban]

The 748RR (your red 90*) shows as not fitting my vehicle when looking at them on Advance Auto's site. I like the 90* boots, gives a cleaner look I think

Maybe also easier to manipulate when trying to pry off without damaging them too.

 

[swathdiver]

Can't argue with the power gains on the Truck Norris cam,

Yeah, I was just going to use the torque cam because it's not supposed to really have any shop, at least it doesn't sound like it from all the videos I've heard even though it's a 111 LSA.
But yeah the truck Norris is definitely going to have some, you could always just turn the RPM up until it smooths out.

There are lots and lots of videos on this camshaft and dyno runs all across the internet, watching a cool video now of one in a 4.8.

 

[iamdub]

Seems to be the go to cam these days, interesting to see some quarter mile runs. Engine dynos tell a story but not real world characteristics IMO.

I would've gone for this if I was actually shopping for a cam when I did mine. They say they're fine with stock converters, and they probably are "just fine". But I think just about anything ~210+ should have an appropriately looser stall.

 

[iamdub]

My wires have ACDelco 5146 on them
View attachment 368492

The 748RR (your red 90*) shows as not fitting my vehicle when looking at them on Advance Auto's site. I like the 90* boots, gives a cleaner look I think

I just compared that pic to the one I took of mine. We have the same coils. I don't know GM's rhyme or reason for how they choose what engine gets what wire style. Regardless, I don't see why the 748RR wouldn't work for yours.

 

[iamdub]

Maybe also easier to manipulate when trying to pry off without damaging them too.

Yes! I give 'em a few little twists side to side then they pull right off.

 

[iamdub]

Can't argue with the power gains on the Truck Norris cam, but with with an LSA of 107, it's going to have a lot of chop at idle. When I did my cam swap, I tried a cam with a 111 LSA (generally the lower the LSA, the more idle chop), but I found that I didn't like the choppy idle for everyday use. The Truck Norris will be even choppier and the 107 LSA will also push the power band higher. Might be a good cam for a supercharger though. I'll be interested to learn what you think of it once it's in.

Tighter LSA = Peak torque at lower RPM.

If the tighter LSA yields more overlap (varies with duration and profile), then you want a wider LSA for a blower. A turbo can benefit from the tighter LSA in terms of spooling.

 

[gooffeyguy]

I just compared that pic to the one I took of mine. We have the same coils. I don't know GM's rhyme or reason for how they choose what engine gets what wire style. Regardless, I don't see why the 748RR wouldn't work for yours.

Only thing I can think of is maybe different valve cover height on some years

 

[iamdub]

Only thing I can think of is maybe different valve cover height on some years

I've never heard of different valve cover heights. I don't know why this would even be a thing. But, it's probably best that we not delve into trying to understand the psychopathy of GM.