just a quick question for a friend...he has a 4.8L silverado reg. cab. is the only difference between the 5.3 and 4.8 the heads? if so, could he just buy a set of 5.3L heads and bolt em on?

 

I think the heads are the same. The added dispacement comes from the crank which creates a longer stroke.

 

The 4.8 has a 3.779 bore and a 3.268 stroke which = 293ci
The 5.3 has a 3.779 bore and a 3.622 stroke which = 325ci

So switching heads from a 5.3 will not give him a 5.3 engine. A good set of heads and cam will give him some good power though.

 

Do they have the same heads? Is the compression in the 4.8 lower then in the 5.3? With less displacement wouldnt the same size combustion chamber in the heads make the compression lower?

-Rob Nap

 

are there any threads on head/cam swaps on 4.8L's

 

It would be the same as all the other LSX engines.

Compresion on the 4.8 is 9.47
Compresion on the 5.3 is 9.49

 

Heads are exactly the same. 4.8s have flat top pistons, and the 5.3 has dished pistons.

 

Oh ok, thanks for the info!

-Rob Nap

 

FACT!!!