Ampex ATR700 4 track head

[chasman33157]

I have an Ampex ATR 700 that I would like to add the extra head to make it a 4 track machine. Are they still available anywhere and if so, how hard is it to install?

 

[stevieb]

If that's a half-track (that means it only records in one direction on the tape, right?) I'd be interested in a trade... Fostex R8?