freshayr
New Member
I want to buy a 440 to rebuild to put in my 68 Coronet. This is just a street car..not a racer. I have found 2, one is a 68 and one is a 72. both have 906 heads. Are the 906 heads a good head?
It was 68 when the B, RB engines went to a common head. Before that the 350,361, 383, 383 RB used a head with smaller ports and valves than a 413 or 440 RB. Also the 426 MAX WEDGE had its own heads with monster ports.The 906 is the casting used on all the big blocks from 68-71 (possibly some used a bit later) Do NOT be misled, there is NO SUCH THING as a "Magnum" head (I.E. what was used on say a 383 Magnum road runner motor)
Let me repeat. They are all the same casting. A 383 2 barrel and a 440 Six Pack used the exact same head casting.
All that said, if what you're building is a "driver" it really doesn't matter if you use 906s, 346s, or 452s. What you will want to have done is have hard exhaust seats installed, and it would be a good idea to have bronze guides (or at least inserts) installed as well. This will just help your motor live on the crappy gas we have to use these days.
Also, since you're going to rebuild the motor anyway it doesn't make much difference what year you use (unless you don't want a cast crank motor so don't get one with the fat balancer)
An "HP" motor is an "HP" only because of the compression ratio, cam, valve springs, carb tuning, distributor timing and advance, and exhaust manifolds. So if you find a smokin hot deal on a 440 that "isn't an "HP"' motor, don't pass on it. You're going to replace everything in the motor that made in an "HP" motor during the rebuild anyway, so it doesn't matter.
Hope this helps