I can buy 'em... I can fly 'em- but I have never installed or un-installed a DF set-up [X(]

I am removing my OS-77/ Dynamax from my JHH A-4 (putting 91 in-) I removed the hex-nut and housing but it looks like there are 3 Allen head bolts in a plate on the shaft- It would appear I have to remove them to get the unit out- is that correct? and if so, where would I find a foot-long angled Allen wrench for that? [X(]

Please, someone walk me through it if you have a minute---I thought I would remove the hex-nut and plastic hub, pull off the fan and grab the engine out the other side...