1500hp? Are you serious?
The most dialed production car in US auto history has 505hp and would easilly be more car than most could handle anywhere near it's limit.
Putting three times the power in a chassis that is 1/2 as capable seems rather absurd to me.
You are talking 3x the power of an Audi R8.
http://www.mulsannescorner.com/audir8-01.html
Is your suspension as good? Do you have the aero package to keep the thing on the ground? Do you have the skill that Tom Kristensen does?
Like Steve-o said, if you can't put it to the ground, if you can't keep from blowing parts out the back (ala the old AAMCO commercial) and if you can't come close to being able to control 1/3 of that whats the point other than to say, "It's got 1500hp."
Honestly I can't imagine a street tire and any suspension that you'd run on the street packaged in a 35-40 year old car is capable of handling more than about 500-600 (Not taking into account the nut behind the wheel.) unless you are just going to putt around town under 4000rpm.