Behold, James W signalled from keyed 4-1000A filament:

Care to expand a bit on this?

Sure!

I found that the RDSon was too high with most MOSFET's. The best I could
attain was a 1/2 volt drop at 1 amp load. When the CB linear came on, it
increased the drop to 6 volts (60 amp draw).

So, I went to the auto wrecker and got a couple of 30 amp relays and a 100
amp contactor for the job and it worked perfect.

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca