These are bare cylinders and head body. No domes, studs,or powervalves. I am keeping everything as spares for mine. We had them on my wifes bike for 10-15hrs of ride time, and took them off because it was too mutch motor for her. These are 421 cylinders, ported by Trinity. They are flawless, they look the same as the day I opened them new (maybe a little dirty). I bought everything as a kit, but I would think that $700 for both would be fair.