while at the shop me and some buddies started looking into some stuff and decided i should put stock ls1 heads and a ls1 cam on the 4.8L, any idea if something will take a dump on me if i do this?

 

I wouldnt unless you are planning on a blower or turbo cause you will lose compression and that cam is not much bigger the the stock 4.8L cam is.

 

That wouldnt be worth the time, money, or effort. Better go big or go home! There are alot of nice cam/head combos out there now to work with. Try an aftermarket set.

 

The bore size would be small enough that the LS1 heads wouldn't flow well due to the cylinder wall shrouding the intake valve. You would be much better off swaping your cam to a peformance grind. A cam swap in an LS motor is so easy it's rediculous. Find a cam with lift under .550 so you can save money by using LS6 springs.

 

4.8s come with 243 heads stock in the NNBS. GM didnt think of shrouding

 

That new 243 casting (799 or whatever) doesn't have different chamber and valve sizes compared to traditional 243 castings?

 

not to mention the ls4 and the 5.3 HO been running 243s for a few years now. the 4.8 and 5.3 have the same bore....the head gasket even says 5.3 HO/5.7

 

My bad I didn't realize they were the same bore, I thought the 4.8 bore was smaller.

 

ok then, well if i get a 5.3 crankshaft, will i then have a 5.3? or are the rod lengths or something else different?

 

Again what he said. Not worth openinig the engine for a 5.3 crank only.