Originally Posted by crash
Would the GXP GT or whatever it is called make better gains from a swap like this?
The GXP G8 got an LS3 instead of an L76. Both the LS3 and L76 are based on the 6.0L LS2.
Both the LS3 and L76 got cylinder heads from the L92. The difference is that the L76 got solid metal valves along with GM's version of engine braking. The LS3 got gas filled hollow valves with no engine braking. The LS3 spins to 6600 RPMS and the L76 spins to 6000RPMs bc of the valve difference.
The LS3 got bumped up to 6.2L and the L76 stayed at 6.0L. Compression is 10.7:1 on the LS3 and 10.4:1 on the L76 because of this.
So basically other than the LS3 stretching the RPMs out further the main difference is the stock horsepower difference between the two....which is about 70HP/40TQ.
If it was a Ford that means it would need another 4-6 PSI to catch up in horsepower. Quite a bit.