i remember someone posting this a long time ago that honda makes a part that screws into the hex bolt fitting on the back of the block but rather than capping it off, has a barb nipple fitting on it. conveniently its the same one used in the endyne kit.

someone help me out with a link to that thread, or if you have the part numbers or even what car it came off of. i've been searching for hours and can't find a damn thing

 

never mind... found it after searching for another 4 hours

https://honda-tech.com/zerothread?id=687222