Which head fits my car?

[PDXAccord79]

Hello,

After getting my aux collars out of the old head (finally) and looking at the new head I noticed that the collars and aux valves themselves don't fit in the head?!? This one is stamped "EF-3" while my old one is stamped "EF-5" The chambers are around a quarter of an inch smaller than my current one and the aux valves are a good 8th of an inch smaller than they should be. The collars won't even screw into the holes it's that off. Any ideas?

[79cord]

I can't claim to have experienced the CVCC engines, & don't know about the any markings on the head but the EF 1600cc (& EG non-CVCC) engines were fitted to the '76-78 Accords before the drivetrains were substantially revised with different bore & stroke late in '78 for '79- model year to the EK 1750cc CVCC (& EL 1602cc non CVCC). Could this be an earlier head?
Or could your "old" head be from a later model like the the "4-port" '81 CVCCII engine (that would still fit your old block)
Might be worth delving into some of the online Honda partsbooks like hondapartsnow and comparing part-numbers / revisions for different years Accords since Honda made so many changes over the years.

[PDXAccord79]

I made a mistake. My head is marked HF-5 and the replacement is HF-3. Everything is smaller than it should be on the replacement.