Hello thanks for looking. My LS1 is knocking and I do not want to disable my car for long. I have a head and cam package yet to be installed. I still need intake, injectors, throttle body, maf, and a tune as funding permits in addition to the knock being repaired. So I was thinking a quick temporary fix could be a 5.3. I am seeing a few 5.3's for sale locally for about $300 - $700 and I and want to know if I can just toss one in, will it work ? For example there is a 5.3 out of a '11 pickup with 110k for $500. Can I strip it down to a long block, add my intake and sensors and be good to go ? Will it run decent on the LS1 tune ? (Stock tune no vats) Do I have to take DOD into consideration ? Should I stay within certain model years ? Will something else work like a 6.0 ? Dose anybody have some advice ?

 

You may be able to score a gen 3 5.3/4.8 pcm along with the motor and it will just plug in to the harness.
Also be ready to drill and tap the alternator bolt next to the crank hub.
Hopefully some more definitive answers will show up soon. Might try ls1tech too.

 

I think the vats on the 5.3/4.8 ecm will need to be disabled along with all the other components no longer in operation. My LS1 ecm has been set up for this. I am wondering if my current set up, the LS1 ecm, wire harness, intake, throttle body, coils, injectors, and sensors will control a 5.3 long block ? I am pretty sure it will but how well will it do it ? Will it be doggy, will it be drivable, or will it even be a noticeable difference ?

 

Youll be able to strip down a 5.3 and move your ls1 stuff over but ho much more would it cost to pick up another ls1 so you done have to do it twice

 

True aluminum ls long blocks are getting pricey so I understand you there. If you're planning on building the ls, have you considered a 3.905 bore 5.3? Iron strength with 347 CI

You may be able to have a tuner load a stock 5.3 tune for the current setup since vats and other components have been removed. If you got a 5.3 ecu you could use it and have vats removed and it should drive correctly. I think I remember a car on tech having problems with ls1 ecu/5.3 block but I don't remember what he did.

 

Thank you all for your input but, I need time and $$$ to repair and finish my ls1, I don't mind doing it twice if it will buy me time to do it better. I need a vehicle like yesterday and have a choice of which one to repair. The 3rd gen looks to be easiest. I went and looked at a rolled 01'Tahoe, the guy fired it up, ac works, it got to operating temp and no check engine light or knocks with good oil pressure. $600 engine, ecu, heat sink coils, wiring harness, all accessories. My truck could use the ac pump and starter plus the other spare parts, I could use another wiring harness and having an extra running lsx around isn't a bad idea. I do not want to mess around with a tuner, this is why I am asking. If the LS1 stuff will work well on the 5.3 this is the way to go, if it won't work well then this is not the best option right now. I also have a set of ls6/243 heads on my ls1 now and may toss them on as well.

 

A 5.3 from a 2011 will either be an LMG (Iron 5.3) or LC9 (Aluminum 5.3).. Both motors already come with 243 or 799 heads, LS2 rods, and flat top pistons, which is a nice bonus. However, unlike the LS1 in your current set-up the 2011 motor is a 58x motor (crank reluctor) Gen IV motor. Physically, the engine will bolt right in (with a few exceptions like knock sensors, valley cover, etc), however the crank will not be compatible with your ECM. Not to mention proper disabling of VVT and displacement on demand (DOD delete kit). The motor is a good value at $600 but I would buy it for parts only (especially if it is a alum block).

If you want a true long block bolt on, I would look for a Gen III 5.3. They don't make as much power in stock trim, but can be had for even less than the quote you received and get you back on the road faster than buying a Gen IV motor. If you get super lucky, you could find an L33 which is a Gen III motor, aluminum block, and 243 heads. Winner Winner.