Think it would be difficult to give a HP increase number. However, after running a rebuilt Rochester on my decent running 235 for 6 months and becoming familar with it's tendency to run "a bit" rich at idle and have some very obvious flat spots when accelerating, changing to the H/W completely eliminated all these little quirks. The 12v electric choke worked flawlessly and the overall improvement in driveability was immediately evident. The improved performance of the H/W motivated me to go with the Carter/Webers on my new setup. I've got some pics in my albums of the H/W install on the stock manifold as well as the C/W setup on my replacement engine. Hope this helps.
Dave
