Model 19 difference to Model 18/ES2

Previously Andrew Jarrett wrote:

Hi,

I have various spares of the 1930's vintage and want to put together a 1936-37 model 19, I am aware that the barrell, conrod and piston are different to the 500cc.

I was looking at my parts list for 1936-37 and the head has a different part number, so I am assuming that the model 19 head is different because of the 82mm bore.

Can anybody confirm that this is the case and if so is it possible to fit a 500 head.

Thanks in advance for any advice.

Cheers

Andy

Forgot about the crank, can anybody give me the dimensions so that I can identify the model 19 crank from a model 18/ES2.

Cheers

Andy