How much HP for my 360 build in my '67 Cuda

If you only plan to drive on the street I would go with the XE268H. My 360 is built with 10.6:1 compression with the XE268H cam and is producing ~370 HP and has run a very traction limited 13.7 second 1/4 at 102 mph.

I am using iron magnum heads which are closed chamber and with the ideal quench the engine runs with no audible detonation just fine on 89 octane so using step dish pistons to get the compression somewhat under 10 should make it run on 87 fine. With aluminum heads you can run more compression (and need to to get the same power) as iron heads. The throttle response is assume with the higher compression, the engine revs instantly and it's very satisfing to drive around.

If you have no plans for the strip then why saddle your self with an engine that will make all it's power in the 3500-6500 range when most of your driving is going to be in the 1500-3000 range? I would go with a cam of less duration and make the car more street friendly.

Also, why would you saddle your self with a requirement for 87 octane on a cruiser when it will only cost an additional $3 more on a typical 14 gal fill-up to use 93 octane. I can see the concern on a daily driver but a toy?

I dont' think I have ever seen a gas station that does not sell premium, a few that don't have the middle grade but with so many of the new performance cars requiring it can't imagine a station staying business long if they didn't.