I bet the issue you have is the power steering pump. ALL FEDERAL PUMPS will not provide proper assist at hi-rpms.... they are a poor design for anything performance orientated, however, MaMopar put them onto hi-performance applications (typically with 3.55 or numerically higher rear axle ratios, as well as certain other applications)..
ONLY the SAGINAW PUMPS will provide the proper assist at hi-rpms. I do autocross and road racing (lots of hi-rpms)... unfortunately, I learned the hard way (a long time ago) with the FEDERAL pumps -- they do not work in hi-rpms. Change to a SAGINAW unit (same as most all GM applications use..) and the problem is cured. ONLY use a SAGINAW pump if you want proper assist at hi-rpms.