Hi everyone. I created this thread just to show people why the 1999-2000 LQ4 6.0L engine found in surburbans and trucks have issues. First let me get to the point, the major differences between the older lq4 and the 01+ lq4 is the cast iron heads, not a big deal for fitment. The crankshaft is longer on the older lq4s on the back where it bolts up to the flexplate. These engines were intended to be only hooked up to the 4L80e transmissions. The newer engines use either a spacer or a different flexplate for the 4l80e. I had this problem with a older camaro conversion i am workin on. We happen to be using a 01 4l60e out of a camaro, and found out that the torque convertor doesnt have room where it meets the flywheel. Where the torque convertor bolts up is in the same exact location as the ls1 but the ls1 flexplate dips in the middle to allow room for the convertor. Looking at this setup you cant change the flexplate on the LQ4 to make it work, you would have to find a aftermarket convertor that has doesnt protude past the mounting points. I know alot of the higher stall convertors are smaller but without playing musical convertors i dont know what would work. To make things easier i found a 2002 ls1 out of a camaro that some jackass rolled "because the ws6 thats was beating him cut him off" and hes apparently sueing the owner of the ws6, what an ***, but he was also dumb enough to sell me his complete ls1 with accessories and wiring for 900 bucks, and i took the convertor too since i had to pull it out. Now that these engines are side by side i can show you what i was talking about. Also because the crankshaft is longer you cannot bolt the newer Ls1 T56 trans to the Lq4.
Ls1 vs. Lq4

Lq4 Longer Crankshaft + Flexplate

Lq4 Flexplate view, notice its flat

Ls1 Shorter Crankshaft + Flexplate

Ls1 Flexplate, notice how it dips in to accommodate the shorter crankshaft and to allow room for the convertor

Ls1 Top view

So let me know if anyone finds a convertor for this, or even if a older 4l60 or 700 will work or even a lt1 t56. Hope this helped a little, i had to buy two engines to figure it out:bang:

 

Yeah, I think that the 'longer crank' issue has been mentioned here at least a couple times, but AFAIK, this is the first time anyone's put pics up to illustrate it. I wouldn't complain if the lighting on a couple of 'em was a bit better, but you get a from me for actually showing the differences. Thanks.

 

Yeah these are cell phone pics, we will be taking more with a nicer camera for clearer shots, just wanted to put this up because we had a real hard time finding out why this is an issue, I have personally spent hours on here and ls1tech, and have had people tell me it should bolt right up, and also people have told me to swap cranks, I wanted to know why but couldn't get any real answers, just that it wont work... but its hard to believe that when others are telling you that it will work. I hope this helps at least one person.

 

Whats your plan for the 2nd LQ?

 

I am either selling it complete or maybe hanging on to it, I have a buyer who wants it for $1000 I might go with that, I wish that It was just 1 year newer...

 

Would 1 year newer fit better?

 

if the engine is 2001 or newer it has a removable spacer which makes it easier to adapt to 4l60, 4l80 or whatever you want. So yes one year newer makes all the difference, also it should have aluminum heads.

 

So basically 01's and up make life a lot easier? Im getting ready to swap an LQ4 into my '88 IROC (currently collecting parts and what not) and I was trying to figure what im going to do about my LT1 T56. I definitely need to convert the LT1 to LS1 style front plate and input, aswell as the bellhousing. Once that's done, I would need to find an adapter to mate the T56 to 01+ LQ4's for perfect fitment?

 

i have heard of this problem as well, glad to see your pics and reserch but is it just with the lq4 or is it w the lq9 as well. and how about the 4.8l and 5.3l was there any problems like this with them you might have run across.

 

very interested in the difference between the lq4 and the lq9 anyone know thanks
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very interested in the difference between the lq4 and the lq9 anyone know thanks

 

I was searching the internet to find out if I could use a 1999-2000 LQ4 with an LT1 T56 and I came across this thread.

Has anybody been able to confirm or deny that this combination works?

I have an LT1 T56 mated to a GEN I 350 and I am hoping I can do this.

Thanks for any new information!

 

Welcome aboard thirdgen.org.

This didn't show T56, but sounds like it should fit. Mock it up and post results.

 

i actually agree, if you have it bolted up to a sbc already theres no reason why a 99-00 lq4 wouldnt fit perfect, or even a 01+ with a crank spacer.

 

Conversely, the 99-00 motors work great if you're not going to change the transmission. A 99 6.0 bolts right up to the TH350 and converter in my wife's 91. Swap in progress.

 

I have a th350 bolted up to my '04 lq4. I used the stock spacer and flywheel and a converter drilled for th350/400 dual pattern. It all bolted together like it was meant to.

 

Will a 700r4 bolt up to a 99 LQ4?

 

I have a buddy of mine using a T56 with an LQ9 engine, no problem.

 

Has anyone tried an LT1 T56 with the '99/'00 blocks yet? I desperately need to know if it works and I don't have a trans on hand to try it out myself. Or what about possibly putting a flywheel and crankshaft from an LS1 in the older LQ4? I need to know by Monday!!!

 

way easier to use ls1 fbody specific t56, lt1 t56 need to be fitted with ls1 front plate and longer input shaft, among other mods. a ls1 flywheel and will work if the lq4 engine is the standard length crank flange. only the 99-00/01 lq4 came with the large flange, as a side benefit, the lq4 long flange is easier to adapt to a th350/400.

 

How would I know if mine has the standard crank flange in order to use an LS1 flywheel? All I know for sure is it's a '99 or'00 block.

 

Well, now I'm really confused....

I'm waiting to get my late model LQ4 with short crank and ALU heads.

Can anybody tell me, what will I need to put together that engine with good old TH400 with old style TQ.

Spacer? Which flywheel (the original one, which is allready on the LQ4 engine or the flat one or my old one, which is on old Chevy 350 block).

Anything else?

 

ok I think I am running into the same problem hoping you can help I have a 6.0 lq4 out of a 2002 gmc 2500 and a 2001 4l60e transmission and a 1997 4l60e transmission. I cant seem to get them to bolt up my torque converter hit my flexplate before my trans and the engine meet with the 1997 trans its about a 1/2 to an 3/4 inch away before my trans will meet my motor and 2001 trans is about 1/4 to 1/2 inch away. but my bolt pattern was not the same for the stock flexplate and my torque converter so I found a 1999 flexplate that seems to have the same pattern for the torque converter. but like I said above my motor and trans are to far about to bolt up because the torque converter hits my flexplate before motor and trans do. what can I do to get it to work? thanks