What makes the 260 and 280Z's so much heavier than the 240? And does the weight greatly affect the cars performance/handeling?

First, Welcome to the club! :classic: :classic:

You will find our arcives very helpful-if you use them!

Second, The simple answers to your questions are:

More stuff, and yes.

a brief explanation of the answers is:

The weight comes from strengthening the frame, adding mandated safety and epa- parts (Catalytic conveter, bigger bumpers with shock mounts). beefier differentials, stronger electrical devices(alternator, more wiring, heavier fuel pump, sway bars, bigger radiator, ...) more emissions controls, etc

Adding weight always changes performance, it lowers the hp/weigh ratio. lowering acceleration times.

It changes the roll center and the moment of inertia of the car, affecting the handling.

Will

when i try to click on the FAQ button i get a screen that sais "You can't access this file directly...", why?

There are a few links that don't work at the moment. FAQ's is one of them.

BUT, FAQ'a isn't where you want to go to find archives.(if that is what you're trying to do) CLick on "FORUMS" at the top of any page, then below the tabs, select "SEARCH" which will take you to a page where you can enter your search criteria.