So, I did a basic power curve comparison vs our Ace CGT Fireball 535.
The Interceptor has about 2 ft-lbs torque more than the 535 Fireball, pretty much all the way from bottom to top. This gives it roughly 2 rwhp more all the way up too, except at the very top where the Interceptor extends its rpm and power advantage up to about 4 rwhp more.
So, given similar weight loads, the Interceptor should have a slight advantage over the Fireball 535 at pretty much anywhere along the rpm range. At the very top rpms above 6000 rpm, the 650 twin would be about 10% stronger than the 535.
I feel okay about this, given the 22% bigger engine with OHC 4-valve short stroke layout with two cylinders. And the 535 gets better mpg while punching above its displacement class.
All in all, the Interceptor should go quite like the old vintage ones, and it looks the retro part. I could imagine myself getting one someday, maybe. Of course, I would mod it!