I will be trying synthetic oil in my stovebolt, yes it might leak a little more, and no I won't be going 7500 miles between oil changes. It will cost more and maybe it is not necessary, but I have been very impressed by the performance of synthetic oils. I work on jet engines for a living and have seen first hand what synthetics can hold up to. My uncle has a 1926 model T ford that he decided to try synthetic in, turns out the brake band that runs in oil became so slippery that he couldn't stop anymore with that brake and had to change back to mineral oil. Whatever you use will be fine as long as you keep it filled and changed regularly. I am amazed that there are always huge forum discussions about oil but very few hard facts or scientific tests to back anything up, I've gone through the synthetic/mineral debate many times with my Harley as well. Good Luck with whatever you choose.
