Well, the '88 front bump stop just bolts on... so we'll have to assume it's the '84-'87 bump stop that's being difficult to install here.
Like many of the finer things in life... just add some lube and pound it in.
If you wish to be gentler, I suppose you could temporarily leave the spring out and use the lower control arm to press
in the poly bump stop (using a hydraulic jack to push the LCA up). Of course, the whole assembly will need to be mounted in the car to do it in this manner.
[This message has been edited by Patrick (edited 01-18-2015).]