1999 silverado 4.8 to 6.0 swap help, truth needed
 

Ok guys, been hearing several different thoughts on a 4.8 to 6.0 swap. Ok, my truck is a 1999 ecsb 4x4 with the 4.8, i want to swap in a 6.0, everyone said it will go right in, any model 6.0 from 1999-06 , no problems, direct swap, THEN, I hear i need to stay away from any 1999-2000 6.0's because they had longer cranks and wont work with my current and stock 4l60e trans, they said to get a 2001-06 6.0 and it would work, just use the 4.8 flexplate, ok, all good. WELL, now im hearing that because my truck is a 1999, that the crank in the original 4.8 is also long, just like the 1999-00 6.0's have, so my original 4.8 flexplate wont work on the 6.0 to use my tranny. so, anyone here ever done the 4.8 to 6.0 swap ON a 1999 truck? If so, whats the truth and what do i need to make it work? remember, i want to keep my stock original 4l60e trans that is in the truck mated to the 4.8 (yes i will build the tranny to hold up to the 6.0)

SO, Truck is a 1999, original 4.8, 4l60e
was told to get 2001-06 6.0 and use my 4.8 flexplate on the 6.0 to use my tranny,
then heard that wont work because my 4.8 is a 1999 model and uses a longer crank, therefore, that flexplate wont work to mate the 6.0 to my trans.....?
So, if my truck were a say, 2003 with 4.8 and 4l60e, then i could get a 6.0 from 2001-06 and slap it right in, but, because its a 1999 that came with a longer crank in the engine, the trans in the truck wont work with the 6.0 because the flexplate..
HELP!!

I've never heard of long crank 4.8

Who told you that?

Moved this to the General discussion for you. You might get more response in there with this type of question.

Use the search feature at the top as this topic has been covered several times.

There has NEVER been a long crank 4.8 with a 4L60E.

01-07 Classic LQ4 will bolt right up using existing 4.8 flexplate.
03-07 Classic LQ9 will bolt right up using existing 4.8 flexplate.

99-00 LQ4 had the long crank with Iron heads.

The truck will run but you will need to have the computer re-tuned. The calibrations for the engines are different.

Like they said above. Good luck with your swap.

I've heard of the 4.8 having a longer crank with the 5speed in the early models. But like you, ive just heard/read this and can't clarify. I would suggest buying a 6.0/80E and swapping that in at once and not worrying with the 60e and a long cranked 4.8

Correct, the 1999 & 2000 model 4.8L engines mated to a manual trans were the only long style crank Gen III engines outside of the same year model 6.0L's.

really want to keep the 4l60e, buddy at work builds them strong enough for the 6.0

so they actually made 2 different cranks for the 4.8, one for the automatic and one for the 5 speed?

Sounds like since you already have an automatic truck a post-2000 6.0 will work just fine for you.
I swapped a 2000 4.8 out for a 2003 6.0 keeping my original transmission and everything else and it worked just fine. Like already mentioned above you'll need a new tune to make it run right.

awesome! what about mileage, will the 6.0 do better than the 4.8 in my application since the power to weight ratio will be better (its an extended cab shortbed and 4x4)? I know the 5.3 does better fuel mileage than the 4.8 in the bigger heavier trucks like this.. 6.0 will remain stock, just a custom tune..