8k rpm ...

I get the OP desire, use to love to drive my Honda Prelude and shift it to it’s 7800 redline and with its something like 4.90 gears. Is that a reason to build an high rpm engine ?

Problem with building a 340 plus like that is gonna need a lot of airflow and make too much power to be able to get into it a lot.

Most times I’d say go with a bigger engine but in this case I’d think it would be easier to accomplish his goals with a 273,
ported out the factory heads or notch the block and run magnum or even 1.88 340/360 heads with pistons that have a quench pad since your gonna need custom pistons anyways, that leaves cam either solid or solid roller, done right should be able to make it reasonably streetable maybe with a peak hp at 7000 rpm or so and a 7500-8000 redline. Wouldn’t be the most powerful car in the world probably 400 hp tops. Add some deep gears and probably be a fun package.

Making power with mainly head flow and trying to get the cam reasonably small for the build level would be the trick in making it more streetable.