first im not a kid in in my mid 50's, ive seen the old hit and miss engines, when i worked at a repair center for oil field equipment to put myself thru college, they had several laying about the shop,which ran the pump jacks back then unfortunately back then i didnt really give them much thought, i picked up a book by peter rooke, on gas engine restoration awhile back, now im getting real interested in these old engines, still cant grasp the electrical system without a engine sitting here, but ill get it, now if i wanted to get one to play with, which would be the most common, [ ie which one has the best chance of finding parts if i need some] or does everything have to be made from scratch these days on a lath? also how much money are you guys having to invest in an old engine to get it to running condition?