Not necessarily. The Chevy type starter solenoid has two purposes. It moves the starter bendix gear to engage the flywheel teeth and once it has traveled all the way to the end of it's stroke, it completes the starter power connection and applies power to starter motor. If there too much resistance in the solenoid control circuit that goes thru key switch and then neutral safety switches, the voltage at the solenoid may be too low to overcome the internal spring and fully engage the solenoid to complete circuit to the starter motor. You will hear a click but the solenoid doesn't travel to the end of stroke to power the starter motor.

Also if the bendix hits flywheel but the teeth don't engage (bad starter alignment), the solenoid won't reach end of stroke to power the starter motor. I've seen where the wrong bolts were used to mount the starter and the starter eventually shifted itself out of alignment. The knurling of the starter bolts should eliminate any side-to-side slop between the bolt and the block and also between the bolt and the starter. If all that's correct, the starter shouldn't budge (assuming the bolts are tight). I've run across a situation on my boat where a "metric" starter was used. Hole in 454 block was 3/8" and hole in starter was 10mm. In that case, a special bolt was needed that had half of the knurling at 3/8" and the other half at 10mm. "Stepped knurling" if you will.

An old solenoid with burnt contacts (for starter motor) will behave the same but since yours are new, I'm ruling that out.

You might try taking out a bolt at a time and sanding the under side of the bolt head and the surface around the bolt hole.

Electrical grounding often gets overlooked both on troubleshooting and maintenance.
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​​A good heavy grease on clean connections will prevent a lot of corrosion, and issues down the road.

I replaced the neutral safety switches maybe 4 or 5 years ago. The ignition switches are original from 1995. I had the Marina install the engines and do the alignment but i did everything else so i may have a wire or several wires that have worked loose. I have time so i guess a complete nut and bolt check is in order. Thanks for the help

Also check that the wires are tight in the crimp ends. That one has got me before.

Yup me too. I actually soldered and shrink wrapped most everything I touched hoping to eliminate that as a problem but as you probably know, there are a million other factory crimp ends that could be a problem.

I have an "Electric Dielectric Grease" that I use on a lot of area's but I know I didn't use it on any of the ground locations. Probably in hindsight that might have been the place to use it?

Dielectric grease is non conductive. I would not use it there.

You have got to be kidding me!! This is the stuff I bought. It only talks about spark plug boots and battery terminals but I have been using it on all possible electrical connections on all of my vehicles. I was using it to control or stop corrosion and keep a good electrical contact.

You’re fine with the dielectric. It will reduce corrosion.