There are still plenty of the 40mm stroke jugs out there but the hardest part is finding a seller who will answer your questions to tell you which stroke size they're set up for or the size and type of the ports. Some of them have really small transfers while others have some really nice ones that only need the casting line cleaned up. You definitely want the larger transfers if you got performance in mind since these are the most difficult to open up but not so bad just doing a quick cleanup. Best thing to Adonis ask the seller what they got and if they don't answer just move on to one who will. For the most part as long as you got the right jug for the right stroke crank you'll end up with a good running and performing engine but if you get a jug set up for the shorter crank or longer crank you'll be spending some time getting the port timing where its going to work best.