I have a 38 p6 with the original flathead 6 engine. I thought it was 201 cid, but, the other night at a show an older gentleman told me he believed it was a 217 cid. He works on forklifts and other equipment that uses these engines and he owned a 40's flathead. He really seemed to know his stuff so I started to doubt what size the engine really was. What size should this engine really be?
He also recommended that I pull the pan and clean it out and then start using 1 quart of regular detergent oil for awhile and slowly work up to using all modern detergent oil. The engine has 42,000 on it and appears to be untouched. I change it often and use non-detergent 30 weight. He said his engine ran better because the old style oil caused sticking valves.
I'm also looking putting on a split exhaust manifold with true dual exhaust. I original planned to do it for the sound, I'm also hoping it might increase power a little. What size exhaust pipes would work the best and what kind of power upgrade can I expect?