If I lower by 3.5”.......

.......using horseshoes on the back and drop spindles with upside down ball joint/end rods will I have to make any other mods for wheel clearance? I currently have standard 14” wheels with 185/80 R14 tyres. Apologies if previously discussed...thx in advance

Yes, dropped/flipped spindles will require coil over/uprated type dampers up front and a lower profile tyre to avoid rubbing. You'll possibly need a shorter rear damper also.

As stated by Clem, shorter shocks. You can mount the front shocks in the rear if they are in good condition, and for the front I would put some shorter gas shocks for stiffness. Also you might be looking at tubbing the front Wheel wells for clearance with those big tires. Last but not least, check clearence between rear frame and driveshaft / IRS Control arm. You can get by with just grinding the lip down and maybe trim the bumpstop a tad.