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?

All of the research material I have seen states that Plymouth did not get the 217 until 1942.
Jim Yergin

Everything I have says it should be a 201. It makes sense now since he told me he had a 40's plymouth with the flathead and he was referring to them as 217 cid.

I just talked to George Asche on the phone. What an interesting guy, I think he would have talked for hours about cars. He's only about 4 hrs. from me, I'm going to have to pay him a visit someday. I think I'm going to buy a split manifold from him. He has all kinds of neat stuff for sale including an overdrive trans. He said it was the nicest one he has ever seen, I wish I had the extra cash.

I've spoken to George Asche a few times myself and know what you mean about him liking to talk. Bought a rebuilt carb from him and he was very helpful. Have you checked out the forum at www.P15-D24.com? It is a great source of information about Mopar flatheads not just P15s and D24s. I have a '41 P12 and use that forum regularly.