mopower440

ok guys, someone has to know for sure, the 100% truth on this.. Heres the deal, i have a 1999 silverado extended cab shortbed 4x4 with the 4.8 engine and 4l60e trans, all original. I want to swap in a 6.0 and keep my 4l60e and stock torque convertor and all, will beef up the trans to hold up to the 6.0.
Ok, From what i have heard, in order to use my stock convertor and 4l60e, i need to find a 2001-up 6.0 to avoid the oddball longer crankshaft. ok, that would be no problem, but i read somewhere yesterday it needed to be a 2004-up to avoid the oddball longer crank, so back to the drawing board.. Does anyone know the truth? I know an LQ9 would bolt right up seeing as they were mated to 4l65e and 4l70e, but most likely it would be an lq4 that was mated to a 4l80e that i would use being as they are cheaper, but, will the lq4 work, even if it is newer than 2001 or will it STILL have the longer crank? I am looking at a 2004 lq4 out of a savanna van and another 2003 lq4 from a 2500 truck, will they work or will they have the dreaded longer crank? I dont wanna mess with having a custom convertor made or any of that, i just want to pull out the 4.8 and install the 6.0 and be done.. anyone know the truth? If all year lq4's will be a problem with the longer crank, i guess ill have to save longer for the lq9, need to know the truth before i buy anything..This is already being done on a tight budget and i sure dont want to order an engine and it not work without custom convertors and all.
Thanks

kazfan30

iTrader: (18)

I am pretty sure you are correct in that only the 99-00 had the spacer built on the crank... if you get a later one then it will have the removable spacer and a "flat flywheel" used for 4l80e's. So just reuse your 5.3 "concaved" flywheel on your 6.0 without the spacer and you will be good to go.

BigKID

iTrader: (5)

IIRC another sanity check would be the iron headed engines (99-00) had the longer crank. You also need to make sure it has a 24x reluctor (01-06) or else you will need a crank signal converter.

mopower440

ok, so for sure i am safe with a 2001-06, even if it is an lq4 that came with a 4l80e originally, it will have a removeable spacer on it, no exceptions? Just wanna be sure because i dont want to order one and it arrive and have the longer crank and then i cant use it. Like i said, it wouldnt be a worry if i get a lq9, but it will probably be an lq4 from a 2500 truck or van..
again, so for sure 2001-06 wont have a longer crank, just the removeable spacer?
Thanks!

kazfan30

iTrader: (18)

Correct.. like bigkid mentioned.. ive never seen one later than a 00 with iron heads that the crank was longer. Ive seen alot lq4s and every one from 01 up had a spacer between the flywheel and crank. The spacer is to move the flywheel out further for the 80e.. but you will just use your oe flywheel. I would keep that flywheel and spacer in case you ever go 80e lol..

mopower440

awesome, thanks! Only other question now is, i have also heard that 1999-2000 4.8's also had the oddball longer crank, if this is true, im screwed because mine is a 1999 with the 4.8...

kazfan30

iTrader: (18)

Not 100% on that. .but seeing alot of 4.8 vans had 4l80e transmissions it does seem very plausible that the van 4.8s could.

53bowtie

iTrader: (6)

My dad's 2000 4.8 did NOT have the longer crank. We swapped it out for an LS1 and it bolted up to the 4L60 just fine. I would think yours does not have the longer crank as I have only heard of the 6.0 engines in the trucks having the longer crank.

1FastBrick

iTrader: (17)

You have nothing to worry about.

The Longer crank 4.8's were only used on the manual transmission and the 4L80E in 99-00. They were NOT used with the 4L60E.

The 6.0L from 99-00 had Iron heads and the long crankshaft.

An LQ4 from 01-07 Classic body style or LQ9 from 02-07 Classic Body style will swap right in.

As mentioned, the LQ4 will need the spacer removed and to use the old fly wheel from your 4.8L.

SnakeOiler

iTrader: (6)

This thread is full of good factual information