All Small Six Head questions

[toms67]

Hello. My first post.
Could someone answer two questions for me ?
I have a stock 200 ci in my 67 mustang coupe. When I got it , it came with an extra head. The casting reads C 9 DE-8090-M
I figure it’s a 250 head but can’t find decode info.
Also I have a spare adjustable rocker assembly. One standoff is oval. Why ?
Thanks
Tom

 

[bubba22349]

Hi and welcome to the Ford six forum! The C9DE-8090-M heads are one of the first Larger Log Heads they can be for a 170, 200 or a 250 Head, with the 170 heads some versions with the (M) they will have the smallest combustion chambers and were a big favorite of the Small Six Hot Roder's to use in the early 1970's on the 200 Six short blocks. Some good Pictures of the Combustion Chambers can help to I. D. that 170 head casting, all of these Large Log Heads will also have the bigger 1 3/4 inch Carb mounting Hole to use the bigger later model Carbs. All the 1969 Up Larger Log Heads will also out flow any of the 1963 1/2 to 1968 early small Log Heads, there are some things needed to be able to use them on the pre 1969 cars such as a different Carb or a Carb adapter and is also better when used along with one of the 1968 up Duel Advance Point or one of the DuraSpark II Distributors too. Many like to use those early adjustable rocker arms on their Six's especially when using one of the better Performance Camshaft Grinds to make it easy for the valve Lash settings, if its the first Rocker stand than that was for oiling. Best of luck on your 67 Mustang Couple build.

 

[MustangMech]

Hi and welcome to the Ford six forum! The C9DE-8090-M heads are one of the first Larger Log Heads they can be for a 170, 200 or a 250 Head, with the 170 heads some versions with the (M) they will have the smallest combustion chambers and were a big favorite of the Small Six Hot Roder's to use in the early 1970's on the 200 Six short blocks. Some good Pictures of the Combustion Chambers can help to I. D. that 170 head casting, all of these Large Log Heads will also have the bigger 1 3/4 inch Carb mounting Hole to use the bigger later model Carbs. All the 1969 Up Larger Log Heads will also out flow any of the 1963 1/2 to 1968 early small Log Heads, there are some things needed to be able to use them on the pre 1969 cars such as a different Carb or a Carb adapter and is also better when used along with one of the 1968 up Duel Advance Point or one of the DuraSpark II Distributors too. Many like to use those early adjustable rocker arms on their Six's especially when using one of the better Performance Camshaft Grinds to make it easy for the valve Lash settings, if its he first Rocker stand than that was for oiling. Best of luck on your 67 Mustang Couple build.

So I’m still learning too, so of the 250 log castings, are they all the same? Or are there any that are better than the others?

 

[bubba22349]

Hi MustangMech, and welcome to the Ford Six Forum! Generally most all of the 200 & 250 Six Large Log Heads will have the same Combustion Chamber Shape and when Stock and uncut they will measure on average at 62-63 CC's. If you really want to learn more about these great little Six's and Proven Techniques on Rebuilding and Moding them for more power you should Pick up these two great books will get you up to speed quickly. Best of luck in your learning.

The Ford Falcon SIX Cylinder PERFORMANCE HANDBOOK
https://www.vintageinlines.com/product-page/the-ford-falcon-six-cylinder-performance-handbook

Ford Inline Six: How to Rebuild and Modify
https://www.vintageinlines.com/product-page/ford-inline-six-how-to-rebuild-and-modify