[blykins]

Most engines that make peak hp in the mid 7000 range will require a fat bank account. Doing it happily and reliably add more to the bill.

Four cylinders have very small main and rod journals, light rods, light pistons, etc. V8's have heavier components, larger bearing sizes, etc. Larger bearing sizes mean higher bearing speed.

A 289 is a very small V8. They don't have much hp and torque to begin with and when you cam them up to make hp up high, hp may go up, but torque goes way down. Horsepower and torque peak rpms go way up. This makes for a very finicky engine on the street. Combining the large overlap with webers will also prove to be a tuning challenge.

The valvetrain parts alone (springs, etc) necessary to support very high rpm use will be very expensive.

Anything can be done, but this sort of engine would not be as fun as what you are thinking.