Or the other goshing sound.

The one that happens when you open the gas cap. My car had always done this very loud and for a long time. Is my tank venting/carbon can system messed up?

Nope, normal.

wow.

On hot day it will blow for almost five seconds.

Perfectly normal, when it doesn't do it I believe the tank check-valve is usually the culprit.

i wonder how the evap systems work in the z.

Why doesnt it use a purge valve to dump (purge) the excess pressure(hc's) back into the intake manifold?

I know alot newer cars use take pressure sensors, shut off valves, and purge valves to moniter take pressures and vapor leaks. But if ours doesnt do that, then why even use a carbon canister? and how are they designed to work?