53bowtie

iTrader: (6)

Hey guys I have a quick question. I'm wanting to get my dad a 5.3 to swap in place of his high mileage 4.8 in his 2000 ecsb. I'm looking at a 2006 lm7 or l33 to try to keep the mileage relatively low. Will there need to be a retune of the 4.8 ecm in order to run the 5.3? I realize a retune would be optimal and we will probably get a black bear tune for it eventually but in the mean time can we drop the 5.3 in and go?

Thanks for the help!

53bowtie

iTrader: (6)

Now that I think about it we will probably just swap the 4.8 intake/injectors/tb to the new motor. So tuning should not be so much of an issue then since we will be reusing all the existing sensors and fuel system correct?

The only difference I can see then would be if the 4.8 injectors are slightly smaller between 2000 and 2006. So I guess the question then becomes how will the 5.3 run with the 4.8 injectors if they are slightly a different size? Also, is there anything else different on the L33 that would prevent a direct swap since the compression and cam are slightly different?

Thanks

TXSZ66AVLANCHE

iTrader: (7)

I drove my 5.7 over 3k miles on the stock 4.8 tune, didn't hurt it. After I finally got the tune the 5.7 had much more power though.

53bowtie

iTrader: (6)

Thanks for the reply. I would assume the L33 would do ok on the 4.8 tune for now and then in the future we can get a tune specific for it. Just didnt want to run into anything unexpected when we swap it out over christmas break because it cant really be down longer than a day.

nonnieselman

iTrader: (10)

your gonna be using the same injectors so that wont matter.

And it will be ok to drive, the MAF and oxygen sensors will keep it close enough in check.

Just get a tune for it soon as you can.

Gadgetized

iTrader: (9)

I assume you know, but you need to run the fuel return like the truck came from the factory.

53bowtie

iTrader: (6)

Was planning to swap intake/fuel rails/tb/etc. off the 4.8 and onto the 5.3 so basically the only things different between the 4.8 and the new 5.3 will be mechanical. All electrical components and fuel components will remain the same and simply be swapped over to the 5.3. I think this should work out fine until we can get a tune.

Thanks for the help guys.