The C8AE-6090-J heads were used on the 135 cars. The C8AE-6090-H heads are the bread and butter heads used on everything non hipo from 68-71. CJ heads are C8OE-6090-N. You need to confirm the last letter on the heads. And the intake number.... It's either a C4AE or C8AE then 9424 or 9425 then a letter after it. That would help.