He'll need some carb and converter work at the very least to cruise at that low an RPM. Unless he under carbs it, he will be trying to cruise on the idle circuit. And that causes some serious compromises to be made. And the converter will not even be close to fully engaged at that RPM pushing all that. Been there, done that. The OP desires economy which calls for a different set of priorities than are usually discussed here. Especially when it comes to strokers and tall gears.

I'm not saying it can't be done. Just sayin' that there will be additional things to consider with that kind of combo. Having torque to spare just moves the issues around, it doesn't necessarily cure 'em.