[Roy928tt]

I've only been messing with motors for 30 yrs, and if there is one thing I've learned, it's that revs are expensive.

As you increase the peak revs, the forces acting on the various internal components of your engine rise exponentially, suddenly you find, you need stronger valve springs, stronger valves, lighter lifters, solid lifters, stronger conrods, lighter pistons, better bearings, a better oiling system etc. etc. etc

You will learn what you need next as your latest rebuild goes bang! again, so you might expect to build half a dozen "experimental" motors till you come up with somthing close to what you were hoping for.

And when you get there you find that it is a peaky, tempermental, pig of a thing to drive and it still makes less power than "brand X" blower system.

To make horsepower you only have to increase the amount of air the engine consumes!

If you really desire a high revving 400hp V8 find yourself a new BMW M3 engine and fit it to a 928.

If you could make a 5 litre 928 engine rev to 8250 rpm it would probably make 500hp, a bit like a M5 V10 really!

Much wiser to simply boost your 928 engine.

Cheers Roy