I went to an Offy intake and a multitude of carbs...MC 2150, Edelbrock 600, Holley 450, And various others including a Predator. Luckily for me I have a workbench full of them from my stock car, But the best carb for a 4.2L hands down is the Holley 390. It is matched well with the low end motor, as well as still having enough left to perform well in the higher RPM's. The Holley 450 wasn't bad, but just a little too much carb for what the motor can handle. Get a 390, you won't regret it.