I' ve just sent the money off for a pair of closed chamber 4v heads which were 'definately 4v'. I took a closer look at the pics and noticed what looks like an 'M' on the head. What I want to know is what difference would there be between the two?

 

i think your confused

 

Ok then, unconfuse me. Thats what forums are for.

 

Where do you think you are seeing an "M" in that picture.

I see is a 4v cleveland head with the 4 cast clearly in the upper right corner and some simple casting numbers in the rocker area

 

On this laptop, it looks like an M. Must email the guy and appologise. Do those casting numbers give a date?

 

The casting numbers you're looking for are going to be on the bottom of the intake ports. 4V closed chamber heads were only manufactured in in the US in '70 and early '71. After that they were all open chamber.

 

They're 4V closed chambers cast on October 1st, 1969. That's what the 9K1 is all about.