I tried to buy a 415 HP 426W M.W. 4 speed Dodge 330 in the spring of 1964, the Dodge Chrysler dealer in Palm Springs, CA (The nearest dealer to me back then) swore up and down that Dodge didn't make a 415 HP 426 wedge, only 365 HP rant
Chrysler Corp had started making the hemi race only cars by then and they quit making the M.W. motors around April 1 was what I learned later whiney
The 426 C.I. wedge motors came in 3 different HP ratings in 1964 only, 365HP, 415Hp and 425 HP.
The 426 Race Hemi motors came in 2 different HP ratings 425 HP for drag racing with the cross ram and two carbs and the single four barrel NASCAR 410 HP scope
Mopar did not have its act together on getting information to the dealers on the hot rod cars they offered whiney
GM and Ford did shruggy

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)