8k rpm ...

Moving the powerband up a few hundred from stock (idle-5000) can start to make your car less street able. That’s why the factory keep on building bigger displacements to reach power goals instead of spinning a smaller engine higher.

Every 500 rpm you move up from stock is huge power difference and cost to a build, for a pure street car you really don’t want to go above a peak power rpm of 5500.

5500 rpm is a lot of rpm for a street car and can make serious power especially 400 cid plus.

Plus to make power up around 8000 rpm your gonna need 350+ cfm heads.

If all you want is rpm maybe go with smaller displacement like a 273 needs a lot less head flow to reach high rpms, especially if you can find a 2.96 crank (248 cid) or a 170 /6 :)