No need for a heat shield or a ford solenoid.
first check the main positive feed to the starter from the battery. Make sure it is not so old that the terminals are corroded. Since it's a new motor, I'll assume the wires are new.
Do you have a good ground wire going from the engine to the battery? this is sometimes done from the alternator bracket. Just be sure it's metal on metal. I had a large gauge black wire going from the battery (-) to the engine block. I also had a flexible ground strap (thin, but 1" wide) going from the engine block to the steering idler arm bolts. You should be ok with just that battery to engine wire for the starter worries.
Next thing to make sure is that your starter's solenoid is engauging the sprocket all the way. If the sprocket doesn't get all the way on the teeth of the flex plate, you will not get any spinning. So check your shims. the clicking sound could be the starter solenoid hitting the flex plate but not "rotating and fully engauging" it.
Usually a starter will not work as well (slow spin) when hot. They don't just fail hot... cool off... and then work again.
good luck. it'll only be hot up there for another week or two.
