First Drive after building, Major shake

Not enuff + Caster, causing "shopping cart" wheel shimmy.
Prob set to factory specs. for bias tires.
Check the alignment setting from the alignment shop, if the caster is near "0", or negative -
Try having the alignment set to attached chart for radial tires.

alignment-specifications.gif

Bad tire/balance, with bad shock is viable, - brakes - not so much.