I just bought a 1977 280z that is 100% original. I was looking for a 240z, but I could not pass this one up. Can I swap the 280 bumpers with the 240?

Mark,

Welcome to the site, and congrats on the purchase of your 280Z!

Unfortunately, your first post here is not one that will make you many friends, as this has been brought up so many times in the past that many of the longtime members will ignore your request (at best). Please familiarize yourself with the excellent search function of this site. You will find lots of info on common new owner questions like this. Searching for 'swap bumpers' gives two pages of threads.

Now, short answer - yes, it can be done, but it is not a simple bolt-on job.