STEPHEN JOHNSON

New to the LS1 world, I just purchased an old car that someone had put an LS! motor and 700r4 tranny in. I man I got this from said that he thought it was a Gen. 3 LS! 4.8L . I would like to know where I can find the ID number on the motor and where I can find the specs. and info on this. thanks

Mercier

iTrader: (15)

On the driver's side of the front of the block you will see the displacement. It should say "4.8/5.3" or "6.0" or similar. You will have to remove the alt and power steering pump I believe. Casting numbers are on the back of the block and will take a bit of work to get to. Heads have a stamping of a 3-digit number on the end that will tell you a lot about them in stock form. If it is Gen III, the lifter valley cover(beneath the intake) will have two ~2" round holes there for knock sensors.

BTW, the reason why the block may say 4.8/5.3 is that they use the same bore/block but the 4.8 is a shorter stroke.

Search this forum for "4.8 specs" or similar and you will find much more info than I have.

HappySalesman

iTrader: (3)

According to this article (http://www.superchevy.com/how-to/eng...e-ls-slugfest/) the only difference is that the 5.3 has a longer stroke. So you'd have to pull the oil pan to look at the casting number on the crank.

murphinator

iTrader: (2)

if its stamped 4.8/5.3 the 5.3 will have dish pistons and the 4.8 will have flat tops , maybe borrow a borescope from autozone ( they have a loaner tool program) and check the piston tops?