Could I take the turbo off of a Grand National and put it on my 99 3.8?

 

no

 

I wouldn't say no is the definate answer, but you will need more than just the turbo to get your engine to run correctly. You'll need custom exhaust manifolds or headers to run the turbo. As well as all the ducting to get the air from the turbo to the intake. You will also need some form of spark retard and a better fuel system. I'm probably forgetting something, but those should be the basics.