5.3 buying advice

[LMJ20]

I found a LM7 out of an 01 1500 with 140k miles on it for $300. Mechanical throttle body.
Problem is, it doesn’t come with a wiring harness. Should this be a deal breaker? What should I look for with this engine? What else should I ask him?




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[derf]

You can get an aftermarket harness if you don't mind dropping down more than twice what you spend on the engine...

https://www.summitracing.com/parts/prf- ... /chevrolet

On the bright side, it's designed for swaps and Painless does really good work on their kit. You will also need to find a computer but those are easy to find.

With 140K on the clock it could have a lot of life left in it or it could be one step away from done. Can you get at it and maybe pull the oil pan to see if there is anything wrong with the bottom end?

[cmaje72]

You should be able to use any truck wiring harness from 1999-2002 if you want to modify it yourself. Its a bit time consuming but not all that hard. I pay $19 at my local pick a part for a harness and ECU.
The bottom ends on these LS engines seem pretty stout. I have been programming ecus for a bunch of the local jeep guys and what I have been seeing is the valve trains failing on the higher mileage engines. I picked one like that up for $150 with 130K on it but I heard it run before he pulled it out. Its been going strong in my Cherokee for 2 years now. Out here in the rust belt the frames rust out on the gm trucks long before the drive trains fail.

[Pillow]

Harness info here if you want to modify a JY harness. Really not hard, but a huge time killer. Also $75 to unlock your ECU with whatever options you want to use. (note not a tune, you will still need the ECU updated for cam swap more powa etc.) \

Or go easy and FITech LS controller. Easy plug and play with new harness. Requires some handheld tuner configuration.

I suggest a full Elring/Reinz gasket kit w new MLS headgaskets. Easy freshen up and just check the cam and bearings for wear and replace as needed... Great time to add a cam

LSs are tough, just make sure the oil pump is good and you should be set!

[JeepManiac]

Does anyone ever run these LS's carb'd? That's what I'm doing if I swap in a 5.3. My buddy has one for sale for $500

[derf]

Why kill all of the great advantages of fuel injection by swapping in a carb? If you're going to stick with a carb, go with an old school Chevy 350.

[ProTouring442]

Speartech can supply a complete new harness and ECM programmed for your needs. I've used them and PSI. Both were good, though I liked the Speartech unit better.

[243]

Changing head gaskets requires new head bolts. But I agree with changing all other gaskets and front and rear seals. Check the timing and knock sensors too.

I would like to find 300 dollar 5.3's or even 4.8's!