The '50 GMC has a separate starter pedal to the right of the gas pedal. I have to be careful because with size 13 shoes, it's easy to depress the gas along with the starter, which can lead to flooding. The starter will operate independent of the key. It truly is an ignition switch and nothing more. The linked video clip shows the procedure on a Chevy of similar vintage. It sounds to me like it was upgraded from a 6 volt to a 12 volt system. The Jimmy is still 6 volt and it doesn't crank anywhere near that fast.
And yeah, no syncromesh on that thing either.
How about those '50s cars from GM that you could start without a key? It sure was a different world back then.
Maybe we should have started a new thread about vintage cars
I have to admit I do love to ask you folks questions and get an answer I can understand and I can say I recall only ever seeing one car my Father owned it was a 50's Wolsely 444 he had before a 666 which I learnt later meant it was a 4 cylinder 44 horse power and so on it was a huge black car that was shown on TV as a police vehicle with a silver bell they rang not nearly as fun as your 50's police cars. But back to the one we had it had bench seats with a armrest in the middle on which I used to sit as I was too small to see over the dash ! No need for car seats back then nor seat belts it didn't have any. When we sold the family home I cleared the garage out and found books about Wolsely's and parts which someone bought for a restoration they were doing. Dad had to sell the big black beast because Mum was learning to drive and refused to drive it because it had " 4 on a tree " as you put it lol so it was got rid of and a more boring Morris 1300 with new hydrolastic suspension in British racing green and no armrest so a cushion had to do instead Oh my how the mind remembers all this is amazing....!!!