I am pretty new to AMCs and I'm trying to learn some things before my 74 Javelin 360 4spd sells. I originally thought I had a pair of 390 heads because I decoded the valve cover tag and it said they were from a 1968 390 head. But now I took the vavle covers off to install 1.6 roller rockers and found the heads were had a number 72 on bothe which appear to be the year. Here are all the numbers off the heads "72" by itself on both heads, then there is a "L-6" or "9-7" if I read it upside down(in the same place on the pass. side is "11-2"), finally the last number is the same on both heads is "3216090-1" or the "9" could have been a "8" I tried to clean it but still couldn't tell.

The other question I have is with these new roller rockers the motor is running worse, it seems that the timing is off even when it is at 0 degrees, I have retarded it and advanced but still seems to miss once in awhile. With roller rockers should I upgrade another part of the motor, I have a Holley carb that is at least a 600, seems to be a race carb because it doesn't have holes the choke. I have a points distributor would it help if I switched to electronic ignition or could the problem be with my distributor. I have replaced the points maybe the distributor is bad. Also it seems that when I get to higher RPM it just flatens out like it's has nothing left, but it didn't do this before I put the roller rockers in. I am lost this car used to be fast but now it feels like the motor is bogging, I lashed the rockers liked it said. I am going to try and get numbers off the carb to find the CFM maybe it needs a rebuild too. I would appreciate any help, thanks everyone.