One question I can answer...is why the engines look different.
It's cause they are.
Tomos originally made the "A3" engine, and later was planning to create an "A35" with the A3 head/A5 Trans, or vice verse, and while they never actually built any - they printed a lot of "A35" manuals and decals.
In truth, they went to the "A5" engine system entire, never made even one "A35"
With me so far ?
So it's either "A3" or "A5" - the engine, and it's easy to tell.
A3 = hexagonal cylinder, longer transmission, shorter stroke.
A5 = square cylinder, shorter transmission, longer stroke.
A lot of A3 and A5 parts cross over, but the pistonarm assembly most certainly does not, and the speedkits WILL NOT FIT an A3 engine, just so you don't blow it trying one in the future.
I am currently doing an experiment in what part changeouts would be required to fit that kit to an A3, if it works I will let the forum know.
As for the engine specs...Let me see if I have a link to anything of that sort.
You can always ask for me, if you need Tomos info, anyhow.