-how much hp can you make on a stock short block befor stuff starts braking? (4.8/5.3/6.0)

-whats a safe max rpm for stock short blocks?

-do all gen 3 motors come factory with aluminum heads?

-whats the c/r of these motors?


thanks

 

I don't think you'd have problems making 400 rwhp safely on a stock shortblock. The parts are good for more power, but it will take a power adder to get that. then you'll find other issues like fuel system and transmission. Most of the internal parts arethe same or very similar to the LS1 / LS6 motors, and those short blocks take a beating and keep going.

I wouldn't want to spin it past 6500 on a stock short block, preferably keep it lower. Will 6500 kill it? Probably not. But if / when you have a problem, higher rpms will be a factor.

All 97+ Gen III motors have aluminum heads, with the exception of the 99-00 LQ4 6 liter truck motors. Other than that, all LS1 / LS6, 4.8, and 5.3 trucks have alum heads.

CR:
LS1 5.7=10:1 - 10.1:1
LS6 5.7=10.5:1
4.8/5.3=9.5:1
LQ4 6L=9.4:1
LQ9 6L=10:1

 

thanks BigTex