Hey guys. I was wondering what the max bore on a 4.8 would be? Could you go .30 over very easy?

 

Since it's the same block and liner used as the 5.3L I would say .030" is no problem. Guys have taken the 5.3L block out .120" so they can use a aftermarket LS1 piston at 3.900". Going that far over you may have to have the cylinder walls checked for thickness but, I know several people have done it.

 

I am one who did the "overbore", check my signature for more.
For sure have the block sonic checked first before going my route, just to make sure there were no casting issues when new. Should cost about $75 or so, good insurance.
Also note the 4.8 and 5.3 share the exact same bore so either block will work for the massive overbore.
Be careful of the "standard" overbore diameters as few to no aftermarket companies make pistons/rings for the smaller truck engines. You can do custom but the extra cost would be better spent for the big overbore to run LS1 internals.
Good luck, it's doable and fun!

 

Thanks alot for the info guys. This will be very helpful.