Originally Posted by 1FastBrick

All you need to do is ask them to look at the 3 digits cast on the outside. 706 and 862 are the ones that would apply to 4.8/5.3L some of the later engines got a 799 casting which is identical to the 243 heads.

Originally Posted by 1Bear

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.

Originally Posted by BillyM151

So I've got a 4.8L 1999 rcsb mated to a manual transmission and I'm planning a 6.0L swap. Will I need the 6.0 w/ a longer crank or will it matter?

Originally Posted by mopower440

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!!

Originally Posted by Wabbit88

I got a 04 chevy Silverado with4.8 computer and my 6.0 works fine on the computer. and also it got plenty of power. Wasn't really that hard.. had to change fuel rails and spark plugs.. also mass airflow senor had to be changed

Originally Posted by BillyM151

So I've got a 4.8L 1999 rcsb mated to a manual transmission and I'm planning a 6.0L swap. Will I need the 6.0 w/ a longer crank or will it matter?

Originally Posted by GMC93

All 6.0s are made to accept your 5speed trans. Its the 2001up 6.0's that have the option to use a 4l60e easily.

Originally Posted by Wabbit88

I got a 04 chevy Silverado with4.8 computer and my 6.0 works fine on the computer. and also it got plenty of power. Wasn't really that hard.. had to change fuel rails and spark plugs.. also mass airflow senor had to be changed

Originally Posted by RedXray

Lets climb aboard Ginger Billy's time machine and travel back in time 9 years.... OP are you still with us... hello?