Help!!!!!!!!!!! 4.8l - 5.3l

I'm in the middle a rebuild and the machine shop just called and said that after measuring the block, he said that I have a 4.8 and not a 5.3. I know the blocks are the same but the cylinder walls are a different size right?

The wrecking yard said the engine came out of a Tahoe. Due to my work seclude, my wife picked up the motor and I didn't even think to tell her to ask to see the donor vehicle. I tore down the motor myself, so I still have all the parts. Is there another way for me to check to see if I have a 4.8 or a 5.3?

Thanks

Carnell

its on the front of the block its cast into it. Like this. http://i83.photobucket.com/albums/j3...9/IMG_0588.jpg
Your machine shop is retarded. 4.8/5.3 is the same blocks, same bore, just different crank.

How much of a hit in performance will I take? My receipt says 5.3L not 4.8 so I have a valid reason to take it back. If I change the crank will it be equal to a 5.3? Is it worth the flight to take a back and get my money back?

if this was just a rebuild not much. The 4.8 and 5.3 only had 15hp difference between them. My 4.8 made 450hp/450 tq on 10psi. Depends on how much performance you were looking for.

What did the pistons you took out look like?

Bad call by the machine shop. The crank and pistons are for a 5.3L so all is good. I'm glad I had a chance to write you guys and look online, or I would have call the wrecking yard and looked like a ass!

Thanks guys for th quick help

Carnell

easiest way to tell with the heads off is if the pistons are flat-tops or not. 4.8 has flat; 5.3 has dished (except the L33 - it had flats too, but was an aluminum block)

I read that last night. I'm glad I took allot of pictures during the tear down

What is the CR of the L33? Wonder if its worth the work to switch the flat tops into my 5.3.

If you look at the pictures, you'll see that the pistons have rims, unless it's been rebuilt, it's a 5.3L. Due to wear, I had to get new pistons. I'm not sure if they are going to be flat tops