cousblake11

I have a 2000 Silverado 1500 Z71 with a LM7 5.3l Vortec, I work at a Chevy dealership and they have a full 1999 6.0l engine just sitting in a tire room, it has everything besides the tranny, there are no cracks that I can see, its been sitting there since 6-1-99 it says, but they want to sell it, and I could probably get it for under $300, so is it a good buy? I no there LS based motors like my 5.3 so it will bolt right up, but what parts from my 5.3 are interchangeable? can the heads I have on my 5.3 fit? the 6.0l has cast heads and my 5.3 has Aluminum heads, what is or isn't interchangeable? also would my 4L60E transmission hold up to a 6.0L? would I have to get a 4L80E for it? what mods would I have to do in order to have a 4L80E in a 1/2 ton Z71 frame? sorry for all the questions im new to the forums and just wanted to see what I should do about my current situation. if anybody knows answers id sure appreciate it.
Thanks,Blake

TexasGMC08

Yes the 4l60e will handle the 6.0 if you go that way. 4.8-6.2 are interchangeable. Save the $300 and spend it on the 5.3 you already have it thats just me. You can stroke the 5.3 to a 383 or 395...but just like the transmission some like the 4l80 some like the 4l60, converting over to the 80e might be a headache idk just from what i read on here.. Some like the 5.3 or 6.0.. Build whats in your budget.

cousblake11

Thanks man, Im looking at most reliable, most power, and good mpg for my lifted Silverado, if i rebuild the 5.3l I want to put a comp cam, roller rockers, FAST 92mm intake and TB, and one day im thinkin about puting a Vortech Supercharger on it, I no gas mileage might not be very good but at least ill have a sweet sounding, running motor, if i did that to the 5.3l what do u think my mpg would be under 10mpg?.......probably

01WS6/tamu

iTrader: (36)

A engine that's not laboring gets good fuel economy. Hence the reason the truck in my sig gets 18-20 with a stock 6.2 and tons of power while guys who opted for 5.3's have crap gas mileage and mod the hell out of them for increased power but usually gain power and no mileage.

You'll have people on here argue the other way but reliability is also a big factor the more you mod stuff. If you drive sanely don't go mudd the hell out of the truck or foot on the floor off of every light a 4L60 will live a happy life behind a 6.0 bone stock add a few goodies and the life and shift quailty go up nothing more than a shift kit/vette servo upgrade and a good tune couple with a 6.0 you will have stock reliability and waay more torque than a 5.3 could produce without heavy mods.

My dad has a 02 extended cab 4x4 he bought new in 01. The 5.3 was a dog when the truck was 6 mos old we put in a crate 6.0 and a mild tune. 12 years later and 155K miles it's our shop truck now and still on the OE transmission and shifts great. It's all in how you treat them if you drive normal they last if you are a foot on the floor driver tow super heavy loads or go mudding with your 4x4 a lot it's life is reduced.

Look at it this way back in the old day's when 305's and 350's roamed the earth 305's where trash can motors just like 5.3's they were ok but waaay underpowered so when they puked or were time for replacement no one wasted their time or money on them they trashed them and put in a 350. You are in the same spot it's tired trash it put in a 6.0 stock with a baby cam for less money than rebuilding a 5.3 and you are money power and torque ahead.
!
From a gm tech/dealer owner this is my experience after growin up in and working on and selling tons and tons of these trucks over the last 34 years
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2011 Sierra, SLT, 6.2 NHT 4:56's, bolt ons, stereo, tint, alarm, onstar delete, GMPP hard tonneau, 2/4 drop, denali 20's, magnaflow muffler stock pipes, FIS custom tune, steel driveshaft

zero2sixT

iTrader: (4)

Why do you think there's something wrong with the 5.3?

What is your budget? What do you want the truck to do?

turbo truck

Leave the 5.3 in but save up for a blower or turbo ...

01WS6/tamu

iTrader: (36)

FI is great but all depends on your overall budget. Reason i suggest 6.0 is they can be had all day long for 600-1500 bucks for running clean ready to roll engines from most salvage yards. At least thats the goin street price in our area for them.

01WS6/tamu

iTrader: (36)

99 model year is the orphan 6.0. The cast heads are junk and there is something goofy about the crank if my memory serves me right. The difference in the flywheel backspacing with that one year only crank wont let it fit a 4l60e. ITHINK?

Heads are dime a dozen for alum stockers or 243 vette heads put a baby cam in it swap a crank and you are good to go. Sorry got off track and didnt actually answer your questions earlier

1FastBrick

iTrader: (17)

Both 99/00 version of the 6.0L had cast Iron heads and the crank with the long rear snout. In 01 they started using a standard production crank in the 6.0 with a spacer between the flywheel and longer bolts.

The early 99-00 6.0 crank will not work with a 4L60E.

To the OP.
As far as heads, the 5.3 heads will bolt on but the valves are smaller as well as the combustion chambers. You might be out side the range of normal pump gas. On a standard LQ4 6.0 I would use a 243/799 head castings or some thing similar. This will bump the compression but still be in the range for normal pump gas. The added compression will allow you to make the most of a cam or other similar mods in the future.

cousblake11

We decided not to buy a 6.0l, I just bought a running 5.3l just like mine and wer gonna rebuild it and put what I want in it, then drop it in my truck when wer done