hey guys , can anyone tell me how to tell the differance between the knuckle head straight leg frame and the panhead straight leg frame. And do i have to remove the heads to install a 57 panhead in the original 57 frame?

 

Knucks were straight leg (off the neck down) Pans were wishbone (off the neck down) If you want to see a pan frame give me an E-Mail

 

Also forgot to say Knuck frames were brazed Pan frames were welded Much better ! I was lucky I have a Knuck in a pan frame Thank God !

 

didnt they go back to straight leg from approx 52-3 57

 

As for the rigid frames I think late 1955 thru 1957 were straight down tubes after pans went to swingarms 58 thru 65 those frames were also straight down tubes

 

thanks guys been a good help, any info on the heads and 57 frame do i need to remove the heads to get the engine in?

 

No the complete engine should go right in

 

sweet i'll go ahead now thanks mate!

 

The knucklehead frame is different than a panhead frame. The front motor mount is higher. If you were to put a knucklehead eng in a panhead frame, you would need a spacer plate at the front motor mount. A panhead eng does not fit in to a knucklehead frame because of the lower back bone/seat post height.(knucklehead heads shorter in height)and because of the front mounts. As other have mentioned at a glance 1955-57 the panhead has straight leg down tubes like the 1947 and earlier knucklehead frames. 1948 to 1954 panhead frames were wishbone leg down tubes. (all had side car loops) 1958 to 1965 swing arm panhead frames and 1966 1969 generator shovelhead swing arm frame??) (all were stright leg down tubes without side car loops)