The inner part of the adapter is thicker than the outer aluminum part. The thickness was uneven overall as it was thicker in the middle than the rest. It took a lot of work to get it working. The idea of this part is great, but the attention to detail, especially in the central phenolic part, is unacceptable. I think I've modified my part enough to work, but I won't know until I get the engine working. If you don't mind paying for something that isn't finished and you don't mind making changes, I wouldn't recommend this part.