Suspension upgrade Qs for '65 coupe

[DeltaMustang65]

Ugh, luckily I was able to remove the front nut & bolt on the leaf spring. Now I can't get the shackle off. I've got the nut off (try not to laugh), but the bolt won't slide out. I've sprayed the area with penetrating oil, SOAKED the area with it, and hammered like mad, but to no avail. I guess this is what happens when nobody rebuilds the suspension in 40+ years.

While waiting for the oil to loosen things up for me, I sanded/primed/painted the new sway bars & shackles semi-flat black. The bronze stuff that they had on there just didn't seem like it was going to afford much protection. Not that I plan on ever driving in bad weather, but meh.

Anyway, I know this message board has been deader than usual lately, but has anyone run into stubborn bolts like this or have any suggestions on getting them off that I haven't thought of?

P.S. Sorry about the chain of questions, and thanks in advance.