Bgf no good, Recomend engine supplier?

So I just got my 15th engine from BGF and it will not even turn over! The piston hits the cylinder head! I've never encountered this problem before but I made a couple base gaskets (thin material) to bring the deck height back to normal and seems to be fine now. Might have to remove one as the engine seems to not have enough compression but will have to ride and see. Rick shi at bgf says he'll send me a head gasket but I will have to pay shipping- not gonna cut it with me. Sell me junk and dont fix it then sell me nothing!

Anyways I am wondering if anyone can recomend an engine kit supplier? I seem to build a bike a month just to sell and I need a good source for my stuff. Opinions please on where you get your supplies

Thanks for the info guys, I will look into them all. I am thinking i might try a four stroke kit soon for my self- gonna hit up AZbill up in fountain hills on that one but I need 3 2strokers now! Thanks for the responses!