what physical difference in parts are the two options for belt drive conversion on shovelhead closed stock primary , electric and kick ?
The inner primary is different with OEM rear belt, clearance for the pulley. Not certain about mainshaft length.
something I learnt a few weeks back , the inner case is supposed to have slotted holes for 4 trans studs on belt models.
I personally have not seen this .
there could be difference in the starter motor housing to primary case . theres was prestolite then hitachi .
possibly the starter gear alignment with the ring gear ?
if you check out BDL indivual part numbers for basket for both kits and if its the same , then its all go .
main shaft didnt change till 1985 - 86 , so same M shaft from 1970 to 85 = 12.47"
Speculation only.... Perhaps the slotted inner primary was for the twin belt Sturgis models, short lived, only 3? Years. I've never seen a slotted inner.
I havent seen one , I cant imagine why it would need to be done if it was in fact done , and yes the only belt model would be sturgis .
theres 2 belts available BE and SE , seems to be some folk have trouble .
possibily after market cases are fractional longer ?
Maybe the reason for slots to allow adjustment..? There is also an idler pulley available to take up slack for the 11mm belt as opposed to the 8 mm..?
chain = 37T / 25T = 1.48:1 , I dont think there is a 25 tooth motor sprocket ?
note : jury is still out on the slotted inner primary case holes . who has an original Sturgis to compare ? not many but still why would there be slots and today wouldnt there be after market cases with slots ? I would still like to see .