Ok, I know this isn't a forced induction question, but this seemed like the closest forum to put this question in.

What I want to do is put the 40v heads on my 32v. My car is a 97 A8 4.2q. I plan to purchase the 40v heads. I'm gonna doubt that anyone here has tackled this, but I figured I would ask anyway. I'm fairly certian the block/head gasket shapeis basically the same. Anyone know if the pattern will match up?

My goal for the car is 500hp, I plan build a mild turbo setup in addition to the heads in order to meet this goal. Shouldn't be too terribly difficult. I am thinking twin GT28r on roughly 6-7psi will get me in the neighborhood of where I want to be.

Before everyone flames me, Yes I know it's big and heavy, but I like to be different. ...and I figure with 500hp on tap it should be pretty damn fun, but still totally streetable.

Thanks in advance for comments/suggestions/ideas.

Dan

If you mean putting on two heads from a 20 valve, they wont match up is my understanding, the porting is different. :(

Lets see, the 4.2 with four valves per cylinder uses timing belts at the front of the engine. The later 5 valves per cylinder V-8's have timing chains at the back of the engine between the block and the clutch housing. Good luck with this conversion. I think you may be urinating into a headwind.

Lets see, the 4.2 with four valves per cylinder uses timing belts at the front of the engine. The later 5 valves per cylinder V-8's have timing chains at the back of the engine between the block and the clutch housing. Good luck with this conversion. I think you may be urinating into a headwind.

Thank you for the information... Didn't know that the newer style engine was a chain style. Good to know though. I think I will have to pursue making the stock engine stronger.