Would a well ported set of heads (like Edelbrock or SM) and a well matched intake get you there? 5 hundo HP with a 318 and say, a solid roller cam with sub 230 degrees or duration?
Could do it with Bloomer heads. They make great power
Not sure how much a 2.08 valve would be shrouded, but high lift 230@50 roller, 13 to 1 compression, good intake and carb, good ring pack, think it could be done pretty easily.