srrodder
Member
- Joined
- Dec 22, 2014
- Messages
- 21
- Reaction score
- 0
- Location
- Virginia
- My Car
- 1969 GT fastback restored
1971 Mach 1 original
I recently initiated a thread regarding Ignition Timing Settings and received a number of great posts in reply. Today I took a close look at the markings on the heads of my 1971 M code engine and find that apparently one is an open chamber 4V head and the other is a closed chamber 4V head. This is indicated by a 4 with a raised dome next to the 4 for the open chamber head and by a 4 and no dome for the closed chamber head – at least that is what I found for the meaning in researching the markings. So I guess sometime in the past an owner had to replace a head. I bought the Mustang 2 years ago, and I guess I should have done some more research and inspection of the car. I also guess I am in the market for a closed chamber 4V head.
I would appreciate it if anyone can verify the meaning of the markings and offer an opinion on how the two different heads would affect the running of the engine.
I would appreciate it if anyone can verify the meaning of the markings and offer an opinion on how the two different heads would affect the running of the engine.