Whats the difference between #6 heads and #7 heads if any?

Thanks

 

One of them have recessed spring pockets... can't tell you which off the top of my head. One of them have rotators on ALL valves, the other only has rotators on just the intake...(or possible JUST the exhaust)

I'm really talking out my ***. I know there are differences but I don't have the heads in front of me.

John

 

#6 heads have rotators (and thus deep spring pockets) on all springs.
#7 heads have them on the exhaust only, but have induction hardened valve seats.
#7a have rotators on both and hardened seats.

Go figure.

 

The reason I asked is I came across a motor in a shop that has 7 heads on them. He wants 100.00 for the whole motor less carb, intake, valve covers. I just had my motor rebuilt, yet it hasn't been installed. I was just curious if those heads would be a better performing head for me. My motor was built with a mild cam, flat top pistons etc. etc.

 

I would buy it just for the spare parts... heads, crank, rods, pan, front cover. Easily worth the $100 if you have the room.

John

 

What engine are you working with?

 

I had my '70 rebuilt. I was wondering if those heads were better than the #6 heads that I have. Or a more desirable head.

Car still needs to go to the body shop so I'm not in a hurry

 

I would buy the 350 for $100 also. Believe it or not but the pre-1973 small blocks are getting harder to find than big blocks at lest they r in Ohio.