The West Coast engine was rated at 46 hp by Hap Alzina although in other places it is rated at 43hp.
They made a lot of small changes most every year. Most of it was marketing, but they should have gained a wee bit of power as they went along.
The Road Rocket was rated at 40 bhp.
The Super Rocket came out with a bit more compression and carb. It was rated 43.
In 1961 the 357 "full race Spitfire cam" was used. That bumped power a bit more. The carb size also went up and the valves were a slightly larger ( Big Valve Super Rocket!)
The east coast and UK bikes were 8.3 to one but Hap Alzina asked for more compression and more chrome for the big California market. He got both, 9 to 1 and chrome all over the place. Even the sidestand is chromed.
That's where the 46 hp rating came from
I don't believe it though.
Irving referred to some of his competitors BHP ratings as " Brochure Horsepower"
The HHC A10s seem to fit that description.
I still like the bike, just wouldn't want to ride it very far or fast.
My frame lugs appear to be of the forged variety up and down? They appear to be identical all around.
A good candidate for fakers?
Dave Comeau has a 63 SR and it is the same. The factory Dyno sheet attached is for a 56 Road Rocket.
Glen