you know your s**t man that's for sure, I have no doubt the L67 has superior torque than the 3900, but stock for stock, the 3900 has the upper hand. Same horsepower, but does it N/A. The 3900 has a better power curve.mod for mod, the edge goes to the 3900. But on an average, how much would you think head porting cost? I might build it up N/A b4 I go turbo.

 

Oh boy lol

 

I know I have the 3500 the 3900 are in the same boat. to be honest I have been getting the little things I like to get done for mine body and interior. the 3900 and 3500 are good running engines but limited on up grades. getting a ls4 from a ss is a little more of a endeavor when there is a lean on some thing. what others have chimed in for is get the little things done that you would like to improve. like rims tail lights different wing on the back the little things that will make it more yours. uniqu.