That V6 3.6 from the Buick must be in some sort of grandpa tune. Isn't one of the hallmarks of a performance DOHC engine that they make power up high? That thing hits peak torque at 2000 rpm.

Here is the 3.6 in Caddy tune.
http://media.gm.com/us/powertrain/en...6L_LY7_STS.pdf

I'll take a wild guess that if they were to go for an SS or GTP application they might get more pep out of it than they do for Buick or Caddy.

 

If we're all consistent, we'd opt for the 3.9L. But marketing forces being what they are... Japanese/Euro makers go the complex and expensive route with their engines mainly because fuel is waaay too expensive for their destination markets... be that as it may, their 4 and 6 cyl engines perform just fine with DOHC. V8s are a different ball game, though, I don't think I'd love the 3.6L engine if GM added two more cylinders to it... I'd still prefer my LS1 to a DOHC V8 anyday.

 

I was surprised at how smooth the 3.9 drives. It sure feels alot like an old 5.0L L-69.