Just changed my generator

[Maricopamike]

I have a 1960 apache 20 with the 283 . I had charging problems at high speeds . I changed the generator repolarized and it charged and ran great in the driveway . I got it out on the highway and now have very bad acceleration . It wont get above 55 mph . Voltage regulator ?? The generator I installed is a 30 amp . It said it was the right one for my truck . I did not change the voltage regulator . While driving it this morning it seems to be charging good no dimming of lights and voltage of the battery is good . Just drives like it has a governor on it now . Any thing that I can test before I order a new voltage regulator ??? Any advice on what may be happening ??