I think you may or may not notice it. The manifold will add about 15 hp. It is a decent jump compared to the total hp now. But will you feel it? I think more people BELIEVE they feel it when actually the car is not that much quicker overall. When I was racing my car, the ONLY thing that ever felt different in my car was how well it left the starting line. But to feel a .10 difference in ET I never did and it did that just based on weather for the day.
70 Chevelle 565 t-400 8.87 151 1.21 60' and 3200lbs Sold 3/18