"the 77-80 heads w/ 61031 casting are a slight improvement over 61030, plus it has the extra coolant temp ports cast over (one less crack/leak point)."
They are both open chamber heads so I would say they are interchangeable.
Rising Sun Bio
2F "Brahma" + Lockright, tach, Warn 8274, FJ60 Power Steering,
no more Sanden OBA
1FZ-FE factory lockers +
Safari intercooled turbo, CDL switch, cup holder, Metric TLC leather, heated seats, JDM switches, PUMA OBA.
Warn M12000 waiting for a bumper.
Limited TRD 2UZ-FE SOLD