Already replaced ignition switch and starter and solenoid and wiring from fire wall down to starter also neutral safety switch appears to be fine.Still sometimes it won't spin and I'm stuck there until it works again. Running out of ideas almost ready to wire in a separate starter switch like a race car,don't really want to though, it is tempting.

Hey a newbie! I ought to toss out something that's been on my mind, about the registration process becoming the board's demise, but I'll focus on the problem at hand.

The nuetual safety switch may be an issue, but I wouldn't know how to go about verifying it because if the switch has an intermittent issue, it can cause a no crank in neutral. If there is a way to bypass it, that would be one way to conduct a long term survey.. (My car's switch was failed in 77 before I bought the car. In all the years, it has never been an issue because I use certain protocall when starting a vehicle.)

I would also focus on resistanc and ground issues. I always start at the begining and work back. Have you checked the battery terminals to cable connections? It never ceaases to amaze me at how many dirty battery-post-to-terminal conections have been the root of the problem. In turn, I have heard that the connections are clean, yet they are filty, and the reports come from people of whom seem to be quite knowledgable in automobile mechanical issues. Clean means that the surfaces look like chrome, not the absence of white crust. If the mating surfaces don't look like chrome, they are filty and create exponential resistance. Ditto for ground connections.

If that's in order, it can be narrowed down as the neutral switch being suspect.

428 Bird,

Do the starting problems happen only when the car is hot? Heat soak will prevent the starter solenoid from working temporarily until things cool down. Do you have headers?

Let us know what you have.

Headers?
Heat shield on starter?
All basic tune-up steps taken to keep the block as cool as possible?

We all have run into this before. On a HOT Friday night the car could just need some time to cool down between starts.

i went through the same thing as you twice!!! with two seprate problems.
you obviously know what wire goes through the firewall down to the starter, just hook a jumper wire onto that wire, then touch it to the battery hot. you will instantly know if the problem is before or after that wire you just jumped. when i did this, it cranked. so i started looking before that wire and found out i had a weak connection from the nuetral safety switch.
the other time was from a old ( cheap) battery. it had enough power to start sometimes, but when the car was warm, and required a little more amps, the battery just didn't have it.

I had that problem for over 2 years ....but it wasnt hot starting ,it was random....finally got it fixed two weeks ago...a bad ign switch...it had a 'burned black spot' on it...$10 part...now (crossing fingers!) it starts all the time

If it makes no noise at all when you attempt to start it, a neutral safety switch is still in the running. If it clicks or something, I have my doubts about the N.S. switch.
The problem in testing for this is that it must be having one of it's little fits while you are testing. Otherwise things will test normal. Just remember, as Amervo brought up, all things electrical begin at the battery, so be sure to validate the battery's integrity as well as the power and ground connections. Hot spots, just as Bjorn pointed out are true indications.
BTW, I run a 428 in mine too. Ton o' Fun wouldn't you say?