Now correct me if I'm wrong, as I need this info for when I do my LQ9 swap (sorry for the thread hijack). When I swap in my 03 LQ9 to my 4L60/65E, I just retain my 5.3 flywheel with no spacer. (my block didn't come with a flywheel or spacer). This is the info I have gathered, but now I just want to be 100% sure.

 

That what i would assume as well. Just be sure to remember to red thread lock your flexplate/flywheel bolts.

 

well if you want to keep the longer crank what has to be done to be able to fit a newer 4l603 on it, is there spacer or something? and what year model 4l80e will bolt up no problem to the longer crank?

 

A 4L60E will not bolt up to the longer crank, unless you have a custom made torque converter I suppose...not sure what year 80E's will work, but I'm sure that some one will chime in. I do know that the newer ones have some improvements that make them stronger than the older ones....they may have changed in 02?

 

There has got to be someone who has use some other transmission besides the 4l80e behind their 99-2000 silverado 6.0L. I am willing to bet almost 100% sure that any SBC transmission will bolt right up to it without a spacer. Im planning on test fitting the Lt1 4l60e i have here, and then ill be buying an Lt1 t56 for it. I am going to also take a bunch of measurements once i get the engine on a stand and in my house.

 

somebody has got to have swapped a 99 six ohh in there truck, the motor im building is for my truck(o3) to there has to be a decent trans i can put behind it

 

Not sure about the other GM trans's, but from what I've learned here, the 4L60E will not bolt up. As I mentioned, maybe someone can manufacture a custom converter or something, but this has been covered, and re-covered numerous times on this board. And a spacer isn't the issue, the crank is too long, so you'd need the opposite of a spacer lol. If you swapped the crank from an 01+ into that 99 block, you could bolt up your 700R4/4L60/4L60E no problem. (I really can't comment on the compatibility of a TH350 or TH400 though as I'm not sure)

 

why would you ever put red loctite on TC bolts? That would make them impossible to get out

 

No the LS1 4l60e is too long. The LT1 4l60e is shorter so is the 700r4, the TH350, the TH400. These transmissions require spacers with the standard short crank LS1. I know because i was going to run a TH400 behind my 68s Ls1. The 99-00 6.0Ls used the SBC/BBC crank length to use the 4l80e which is based on a TH400 platform. Rather than using a spacer they just machined the crank longer. The 700r4, TH350, TH400, LT1 4l60E should ALL fit from everything i know. I am questioning if an LT1 t56 will fit.

 

I said flex plate/flywheel. The bolts that go into your crank, and the bolts that hold on your pressure plate if manual. I've had these back out. Use blue thread locker for your converter bolts.

And red threadlocker is not impossible to remove. The M16 (i think they are) crank pulley bolts are read thread locked from the factory. As large a bolt and thread pitch as those bolts are, they are still removable, even without heat.