The Type 89 at Tsuchiura is restored to running condition but the interior is only roughed in. Many components are missing. I was able to find this image of where the firewall is supposed to be:
Of more help are the line drawings below. They are from an excellent article on the Type 89 found in an old issue of Wild Mook Magazine from the 1970's. I was able to translate the Japanese captions on some of the drawings. Hopefully I'll have time translate the whol article someday. Retirement can't be that far off can it? Many thanks to Tomas Enerdal for a scan of the article.