Need a plan - component selection for restoring 68 340 that runs on 91 oct

If you lower the compression with pistons below the deck you are building a 73 340 not a 68
HP dam is a dog in those motors till you get it really wound up that's why the loosend up the converters
Remember when GM went to the "switch pitch" to get the rpm up on takeoff same problem
it will pull hard if you shift it down but just stepping on the gs it will be flat
not my kind of fun
why not just build it right for today's gas