I recently posted about my plugs burning too clean and remembered that I installed a new exhaust shudder in my 1975 165hp L 6 last winter when I replaced the manifold. There was no shudder at all in my exhaust when I got it. My question is ..could this slightly lower the engine RPMs and top speed? That and the manifold would be the only things that are different from the previous summer. . What do you guys think?