Buying 67-72 questions - suspension/wheels

[agnes the dog]

Hi,

First post here. I just sold my motorcycle to start a father/son truck build project. I am very partial to the 67-72 short bed Chevys. If I had a choice, I'd probably go for a step bed over the fleet bed, but I like them both. I would also prefer a V8 and lower it. Having looked for a couple weeks (and some searches - not new to the value of forums!), I am coming up with some questions.

I see that some trucks have leaf springs in the rear while others have coils. What determines which springs a truck will likely have?

Also, I see that some trucks have 6 lug wheels and others have 5. What determines how many lugs a truck will have?

Is there any cost/difficulty difference or benefits between the leaf/coils and 5/6 lugs when it comes time to put new wheels on and lower the truck.

This won't be my first truck, but it will be my first old truck. If you guys have any advice for a guy just starting out, please feel free to chime in.

Thanks,

JJ