When I switched from a 3.5 to a stock Morgan/Rover 3.9 it was not HP I noticed. But the expanded RPM range. For the first time I could use 3rd gear and leave it in 3rd while I drove the steep, twisty, back roads of Northern California. The 3.73 rear axle ratio I had helped a lot. I have driven a Corvette powered +8+ quite a lot. I don't think it is HP that is the big player. But the right gear ratios for Your driving style I think are paramount. My RPM range is 1,500 to 5,500 RPM with a stock 3.9 and an Edelbrock Carb. Simon probably could tell Me how to get a larger power range.
