I have a 84 elky and a manual for a 87 is the manual any good or what parts of it wil be useful to me.

I would assume so.. But you know what "they" say about assuming. :oops:

Yes, your manual should be fine to use. The only problems you might have, should be covered in the manual anyway, because the manual covers just about every version of the 5th gen elky. Whether you have a 4.6L or a 5.0L, or a 17 gallon or 20 or 22 gallon gas tank. Your radio systems (unless custom of course). You should be fine.