Seems like the Cayenne Turbo motor would fit... granted, it would cost more than the 928 it went into... but there are some crazy 928 folks out there.

It'd be cheaper just to add a turbo or supercharger to a 928 motor and get as much
if not more power. Plus the Cayenne motor is too tall for the 928 engine bay. So unless
you got a "free" Cayenne motor laying around it wouldn't be very practical. But as you
say there are a lot of crazy 928 folks around.

that would be sick. are the cayenne motors based on the 928's?

No. AFAIK no parts are even similar.
The Cayenne S only makes 405 hp, not enough improvement over an S4 which with some exhaust and tuning should be 350+ anyways (at the crank). You should spend some time driving a good one first before you worry about it being slow.

Cayenne motor may be more work than it's worth. A refreshed 928 S4 motor with a s/c may do the trick.

I have 928s with 350 chevrolette engine..
now I want to swap for ls1 engine it will be more fun

Actually, someone we all know has: Porsche is reviving the 928 via a 2-door coupe version of the Panamera. Look for it next fall. (PS It's a secret.)

good thing on the cayenne motor is that it is timing chain...than the timing belt 928

Timing chains wear out as well. Sure they last longer but harder to replace when they do wear out.

$5200 puts a turbo kit + full exhaust on a 32v 928, gives 450hp/500tq @ 5-6psi w/o an intercooler...then you can add the intercooler.

Ask me how I know.

I had a friend considering this and we came to the same conclusion, your better off boosting the stock motor... better numbers, and more budget friendly with ALOT less headaches.