Horsepower Estimate?
We don’t know the details or quality of the build, or the assembly, or the tune. Very best case IMO, 340 hp. Worst case, 270hp.
The OP is 2 hrs from three drag strips. Said differently, the answer is 2 hrs. away. And he’d learn so much more.
To the OP, if you want meaningful information on how the car and engine performs and what to do to make it better, go to the track.
If you want to tell people the hp, tell them the highest number stated on this thread. How would anyone know differently?