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First of all, thanks in advance for any help. I'm in the middle of swap on a 2003 GMC 1500 sierra and it originally had a 5.3 that engine went bye bye so I decided to upgrade to a lq4 6.0 instead of a lm7 5.3. I am running the original 4l60e and being a tech, I'm not worried bout the life of it. I drive slow and don't tow much. When it goes out, then I will consider a swap or building the 4l60e. I made sure to order a lq4 from a 2001 or newer so I would get a short crank. I ordered a atk reman engine and it has the 317 aluminum heads. I assumed this meant it was a 2001 or newer and didn't even bother to check the crank. Now I'm comparing the crank and my reman crank looks longer. Is this going to be a problem? I'm hoping to get this swap done this weekend but it looks like I might to send it back. Reman lq4 crank Original lm7 crank Original 4l60e flexplate
Here’s a 441 I just wrapped up with a standard Length crank flange. Looks just like the LQ you have. I’ve never seen a flange as short as the other one you have pictured. It seems like the long flange LQ’s were all iron headed engines? Picture for reference...
Yeah looks like you have the long crankshaft. You can look on the blocks date stamp on the right bank in front of cylinder #2 and decipher the code. BUT since the engine came from a rebuilder it could have a hodgepodge of different year parts. If the block code says 99-00 it probably coincides with the long crankshaft.
Can I use flat flexplate for 4l60e and make it work?
I don't think so, It's how the converter pilot fits to the crank. I've read you can have a custom LS converter built (if I recall correctly) with a th400 pilot that will fit the long crankshaft. What are the date code numbers on front of the block?
Block manufacture date is April 10th 2005 so you have a late GEN 3 block with the early 6.0L (99-00) long crankshaft. I'd call the rebuilder and tell them they sent the wrong engine for your application, they should make it good. You can make it work but it's gonna be a headache and might get expensive with a custom converter that's not easy replaceable if the need arises.
You have a short snout crank which is correct for your application. You should be no problem to reuse that flexplate.
You're correct sir. Sorry for the typo. For it being a "straight swap" I wasn't able to get this information easy on the webs. Hopefully somebody will search this issue in the future and find some help on this post. Now to finish my swap!
Anybody have recommendations for a tuner? I'm in California so I plan on running the stock tune until after smog and then buying a spare pcm to have tuned for the 6.0. Not looking for performance. This is a grocery getting DD. I asked a wrenching yard and he says that he sells lq4s all day for swaps from a 5.3 and it will run on stock tune but recommends a custom tune.
You're correct sir. Sorry for the typo. For it being a "straight swap" I wasn't able to get this information easy on the webs. Hopefully somebody will search this issue in the future and find some help on this post. Now to finish my swap!
Anybody have recommendations for a tuner? I'm in California so I plan on running the stock tune until after smog and then buying a spare pcm to have tuned for the 6.0. Not looking for performance. This is a grocery getting DD. I asked a wrenching yard and he says that he sells lq4s all day for swaps from a 5.3 and it will run on stock tune but recommends a custom tune.
Where abouts in California?
It should run on the stock 5.3L calibration, but the stock calibration can be updated to reflect its actual displacement.
This should not affect its ability to have a smog check performed.
07-31-2020, 09:23 PM
LQ4 crank short vs long 
