Hardened Valve Seats for unleaded gas

Do I need to install hardened seats in my Dove heads to run unleaded fuel? What year did they start doing that? I have a another set of heads out of a 77 Mercury. Would they have hard seats? Is it a necessity to add the hard seats in a street cruiser. Sorry for all the question. Just haven't built a street motor in awhile.

The 77s will be ok, but the doves will need the hardened seats.
and the 77 heads will lower your compression and you wont need new pistons, leave them as they are.

512Fairlane wrote:Do I need to install hardened seats in my Dove heads to run unleaded fuel? What year did they start doing that? I have a another set of heads out of a 77 Mercury. Would they have hard seats? Is it a necessity to add the hard seats in a street cruiser. Sorry for all the question. Just haven't built a street motor in awhile.

The factory started induction hardening exhaust seats at the end of 1973.

I figured the D3 heads would be OK. I know I had new guides installed when I had these heads done back in the mid 90's but I can't remember if we put seats in them or not. The D3's I have would need to be gone through but they might solve both of my problems. I had a fair amount of work in the DOVE's.

Show & Tell:

Below is a picture of a D3VE head having it's bowls enlarged on the valve & seat machine and you can plainly see in the seat area of the exhaust only, the induction hardened material which is the darker ring around the cut exhaust bowls where the new seats will be recut:



Paul

Which of these would be cheaper? Have the valve job, heads surfaced, and machine the pedestals on the D3 heads for the mechanical cam or have hardened seats put in the Dove heads? What makes a better street combination with everthing else being equal-DOVE heads with dished pistons or D3VE heads with flat tops?

The Doves have slightly better ports and combustion chambers IMO.