[robertsjm711]

Mid November 2017: Engine removal. Again.

Had to remove engine to pull pan and check crank to ensure it is a 5.3l vs a 4.8l.

When I bought it last summer from a guy on Craigslist, I was told it was a 5.3l from a 2001 Silverado. Looked good and taken care of, even mounded properly on a pallet. He didn't have the VIN as he said he had already scrapped the donor truck. He only wanted the trans for his truck.

So I took it home and started to clean and rewire the harness. I found injectors for a Flex-Fuel, and they didn't make a 5.3 Flex in 2001. (Second strike, one being no VIN). There are no external markings on these engines to distinguish, thanks GM. I then found a tab on the head gaskets the was stamped "4,8". Now I go into panic mode, strike 3. I texted the seller, and after a couple texts asking firmly for the VIN he would not respond. I looked at the top of the pistons through the spark plug holes and could see (~90% sure) dish top pistons that pointed toward the 5.3l. It was enough for me to install the engine for mock up but it has bothered me not having hard proof.

Which leads me to now, removing the pan and checking crank casting numbers. Crank are 12552216, pistons are 12555820 and rods are 143, all 5.3l parts. Pan gaskets are not cheap, but worth the piece of mind.

After all this I am confident it is a late 2002 or early 2003 Flex Fuel 5.3. I have read they started flex in 5.3's in 2002-2003 depending on source and started DBW in 2003.