I purchased a 99' LQ4 before I knew the differences about the 99/00' models.

I intend to mate it to a 700r4, but cant find any information on if this particular model will work? Aside from swapping in a shorter crank, do I have any other options?

Ive got it bolted together now, and aside from having to oval out the torque converter holes on flywheel, it fits. Just because it fits though, I dont want to assume it'll run properly, and I'd rather check in and find out the facts before really screwing it up.

Im getting mixed signals from various sites saying yes it will, and no it wont. Some are saying using a flat plate without a spacer will work. Others are saying the only transmissions that will fit are the 4L80E, TH400 and TH350

 

Using the older trans it will work fine on the longer crank

You cant use the T56 and LS1 style 4L60E with that crank

 

Beautiful. Thats what I like to hear. Just use the flat flexplate without spacer to compensate for the longer crank?

 

That's how I understand it, but I haven't tried it. I am sure that whenever you can bolt up a TH350, TH400, or PG, you can also bolt up a 700R-4. I think the LT1 T56 would be easier to adapt than the LS1 T56. I researched all this before I committed to my 4.8

 

Exactly

 

Interesting, never heard of this. I bought an LQ4 rotating assembly and I'm unsure on what year it is. I know it came from an older style (rounded front end) 2500. I'm going with a TH400 anyways, just wondering how I find out if it has the long crank.

 

I know the early LQ4 cranks were .400" longer than the short cranks, but I don't know how to tell you to measure a loose crank so you know which one you have.

 

Found out mine is a long crank. From what I'm reading a standard flex plate works with out a spacer but a SBC style converter has to be used?

 

SBC style converter applies only to 4L60Es and variants
4L80E's were ALL SBC style, hence the adapter used on ALL of them

Since its used look at the wear mark from the RMS. If its near the edge of the flange its the short crank. If its about 1/2" from the edge, then its the long crank

When using a flat flexplate, the adapter acts as a spacer and is required. This puts the starter ring into correct position and receives the converter nub

When using a 4L60E dished flexplate, the adapter goes on the end to catch the converter only