Re: AMC 304-401 Heads alike?
Jeep Freak is right. Actually the 290,304,343,360,390,& 401 heads will all work. But there is one thing you need to watch out for, the older motors(290,some 304's,343, & 390's) had different bolt holes for the intake. I am actually using an old style set of 360 heads that are very closed chambered with screw-in studs and using chevy Crain roller rockers. I used a newer style Eldebrock intake and took a drimmel tool to slot the center bolt holes to match the intake gasket and put the thing on. If you take any V8 intake gasket and look at the center bolt holes you will see that they are slotted to fit the new style or the old style.
Any way, sorry to be so long winded, my .02.