Replacing injectors is easy. You'll need a deep 27mm socket. Make sure the inside is deep enough as some such as impact sockets have shoulders that make them not so deep in effect. The one I got at Home Depot was cheaper and fit better than the Sears one.
Don't forget new heat shields and note which way the heat shields are installed.
I'm not sure about 617s but there might be value in replacing the delivery valve seals while you're at it.
If you can do a 0-60mph run in 15 seconds I doubt you'll gain anything from replacing the injectors.
See if a station near you sells biodiesel. Check the ARCO website as some ARCO stations sell the stuff.
If the stuff if offered from a regular pump then it's just a matter of buying it.
If you go with something like waste vegetable oil (WVO) then you have to consider a heater of some sort because that stuff will solidify overnight or sooner in cold climates, and also a filter so you don't get bits of french fries and the Colonel's herbs and spices in your fuel tank. Check out www.greasel.com.