I need some insight on a motor swap

[iamdub]

These are what I found, honestly I've only been putting 87 in the tank

It's a FlexFuel vehicle. You can run up to 85% Ethanol (E85). Don't confuse this with the grades of octane (87, 89, 91, 93...). Most standard fuels for all vehicles contain up to 10% Ethanol (E10). E85 is not an octane rating of 85, it just means the blend is 85% Ethanol and 15% regular gasoline. Your L59 is perfectly fine on 87 octane. The higher grades aren't necessary. With a performance engine, higher grades may be required. So, factor this in when deciding what you want. High compression and/or advanced timing requires higher octane. Or, since yours is FlexFuel, you can run that. E85 from the pump has as much octane rating as 91-93 if not higher.

My combo and tune requires high octane. Of course, that's the most expensive fuel. But mine is FlexFuel so I run E85- the cheapest fuel, but has the same or higher octane rating so it's safe. I lose fuel economy, but the loss doesn't outweigh the cost savings. I just have to refuel more often. I keep tabs on where E85 is available where I drive and plan ahead.

If E85 isn't a good option for you, then you'll be forced to use premium or select your engine build and tune options based on the fuel you're willing to pay for.

 

[triker97]

Then don't waste your money. If you must spend, do so wisely, get more bang for your buck.
Your SPID sticker says GU6.
Unfortunately, GU6 is 3.42, which sucks sweaty arse.
You could very easily upgrade that RWD axle from 3.42, to 4.10, AND add a torque sensing limited slip differential, for UNDER $1900.

(That $3800 engine - before installation - could be replicated or even improved upon, for $2850 installed, by a clever shopper with time on his side.)

Back to topic:
4.10 would actually be a good investment, as your metro / urban stop'n'go MpG would actually improve.
4.10 MIGHT cost 2 - 4 highway MpG, depending on how you drive it, but it might be worth the extra SMILES per gallon to you.

My Tahoe has GT4 - that's 3.73 - and I'm sorely dissatisfied; I want 4.10 myself, as soon as I can afford it.
If I had your XL, just before the pcm retune that you should also do, I'd've corrected GM's mistake of 3.42, and upgraded to 4.10.

Is there anywhere I could find a chart or something that explains the glovebox list?? I'll definitely look into a new diff also

 

[Marky Dissod]

anywhere I could find a chart or something that explains the glovebox list?

duckduckgo will find an RPO decoder. This forum has RPO decoder links posted; hopefully the links haven't expired or changed.

I'll definitely look into a new diff also.

It'd be far wiser for you to upgrade the 3.42 to 4.10 first, and easier on your wallet too.
I'd actually be willing to bet that a 6.0L XL with 3.42 would not be as quick as a 5.3L XL with 4.10.
The 5.3L XL with 4.10 would have spent less money, and would effectively be getting money back on the metro / urban MpG improvement.
Just sayin ...

 

[iamdub]

Great questions, ok so first this is my daily driver, so I don't wanna go too crazy with the power. What I want to do is be able to accelerate better, burn a little bit of rubber every now and then and have a decent amount of HP for this rig. I don't do any towing, but you never know I might need to one day. I'm sorry I don't have all my cards in order for all this, but thats why I posted here, thank yall

You don't need anything too crazy. 425-ish SMART horses would be plenty and isn't so lofty that you're making major sacrifices. The cam choice would be the most important factor. A mild-moderate cam in a 6.0 with all the supporting mods (appropriate compression ratio, exhaust, etc.), a SLIGHTLY looser stall, 3.73 rear gears or 4.10 if you want a little more off-the-line punch and don't mind a small loss in cruising MPG, an appropriately-built trans and a good tune would make for a stout but reliable setup.

 

[strutaeng]

2wd? I vote 4L80e swap and never look back.

I think you can swap a RPO code AXN 14 bolt 9.5" rear axle too. Regear to something to suits your needs, probably 3.73 or 4.10s.

THEN you can build on the engine.

 

[triker97]

You don't need anything too crazy. 425-ish SMART horses would be plenty and isn't so lofty that you're making major sacrifices. The cam choice would be the most important factor. A mild-moderate cam in a 6.0 with all the supporting mods (appropriate compression ratio, exhaust, etc.), a SLIGHTLY looser stall, 3.73 rear gears or 4.10 if you want a little more off-the-line punch and don't mind a small loss in cruising MPG, an appropriately-built trans and a good tune would make for a stout but reliable setup.

So what if I want to just get the max life out the truck? Would a engine and tranny rebuild, along with a updated rear diff. be worth it?

 

[Marky Dissod]

You can definitely get a used 6.0L and have it rebuilt for well under $3800.

IFF you upgrade to a 6.0L, I could understand 3.73, MAYBE?
Bear in mind that TrailBlazers SS came with 6.0L V8s, 4L60Es, and 4.10.

 

[triker97]

2wd? I vote 4L80e swap and never look back.

I think you can swap a RPO code AXN 14 bolt 9.5" rear axle too. Regear to something to suits your needs, probably 3.73 or 4.10s.

THEN you can build on the engine.

So rear end, engine then tranny?

 

[Marky Dissod]

So what if I want to just get the max life out the truck?
Would an engine and tranny rebuild, along with a updated rear diff. be worth it?

If you do not need a new engine now, save up for a 6.0L that you can upgrade with choice parts.
Same goes for the 4L60E - although, if you plan on working or playing hard with your XL, a 4L80E may be wiser in the very extreme long run.

If you've enough space to store a 6.0L V8 and a 4L60E, search the junkyards, buy them, get them rebuilt / upgraded to your taste, THEN install them in your XL whenever you bloody well feel like it.

If not:
change the engine oil every 4000 miles or less with synthetic - preferably GroupIV synthetic
change the ATF every 2 years or 40,000 miles with DexRon6

 

[Marky Dissod]

So rear end, engine then tranny?

No.
Rear axle, transmission, THEN engine.
Upgrading the axle will actually make things easier on the 4L60E, it might even last a lil bit longer.
Upgrading the 4L60E before the engine will ensure that it can handle the upcoming engine upgrade.

If you upgrade the engine before the 4L60E, and then the 4L60E breaks before you're ready to rebuild / upgrade it, you may curse yself for not heeding this advice, especially if your significant other manages to hold it over your head and convinces you to drive a cheezyer vehicle.

For best results, upgrade vehicles from back to front, and from bottom up.