They must be C90E castings which would be '69 351 heads. They are significantly better than E7's. You should port the exhaust side a little. You can install larger valves for a significant improvement too. The 351 heads should have srew in studs put in and you will need to change rocker arms to the adjustable type. Additionally, you will not have the needed hole for air injection if smog is an issue in your state.
OOPs... the E7s are better all the way .... with one exception... the E7s have smaller valves than the C9s ( 351W heads) ... yes the C9 and the D0 heads off the 351Ws USED to be thing.. when the heads were all choked up with huge EGR tubes ( not bumps) in the late 60s and early 80s!! then the E7s came out with better port and bowl designs and just a small egr bump!! Plus you will need hard seats for unleaded, possible guides, valves, of course if you go to screw in studs, and port work for the C90E heads...... the cost is FAR beyond that of doing the E7s!! and E7s will pull all kinds of power!! So, get out of the 60s!! cool??
The C9's flow 20 cfm more in stock trim on the intake side than E7's. All these heads belong in the 60's. Heart shaped combustion chambers came out in the late 50's and neither of these heads even have that! I respect the opinions of Thumper, but I must respectfully disagree on this issue.
Yes.. there are a few more cfm from the C9s, I guess the point I was trying to make was the cost of getting the few more cfm in having to machine the heads for todays fuel. My own experiance in the mid 70s , was I went .3 slower with C9s and 194/16 valves installed.. the 289s were a more powerfull head on the combo I was running then... (11:1 , solid cam). with the older heads you are going to put a lot of money in to make them work with the fuel of today!! and then you have a heaveyer head than the e7s and more money in them...??
I agree, if you have the choice, use the later heads. I did a cost comparision between reworking a set of 70 something 302 heads, with the small, 54 cc chambers, that I have, etc, and buying used GT40s. After including installing bigger valves and seats, milling, valve job, springs, new rockers and pushrods, (and, or guideplates), modification for studs and studs, a set of iron Gt40s was cheaper! About $700, with springs, milliing, and valve job, on the car!
The GT40s bolt on with stock rocker stuff, and run easily to 6k.
Old windsor heads are old school. GT-40 irons are kind of hard to find but I'd go with that. Of course, if you've got 600 laying around, buy those CNC ported E7TEs. I think powerheads (or something like) makes them. You trade in your old heads and they send you a set ported out on their CNC. Sounds like a pretty good deal.
Im gonna look into them.The heads have already been machined,new vavle guides,new valves,new double springs,vavle spring shims,roller rockers,hardened seats installed, and everything has already been checked out.The only thing I had to pay for was to get them checked out.I like the sound of that place that will trade heads.and yeah I know there will still be some price to it.Thanks alot guys