I am looking for biilboard charts for the artists from the group Jimmy
Briscoe and the little beavers from 1970-1980

Hi derriel,
After doing research on your question for awhile I came up with only
one option for you. I have written to Billboard and asked for the
details and charges for getting the information you want. They replied
that their charts come in many formats and would be very time
consuming if I didn't inform them of the format you would like. So
maybe you would like to give them the information and they will then
set the rate.

Quoted from their site:
http://www.billboard.com/billboard/research/index.jsp
"Reproductions are available (color or B&W) of all past charts.
Resources include chart data and articles dating back to the early
1900s. Call or write for pricing."
Their contact info is:
research@billboard.com
Billboard Research
770 Broadway, New York, NY 10003
Phone: 646-654-4633
Fax: 646-654-4671 or 4672 

I hope this helps in your search. I wish I could have done more for
you.
Best regards,
rainbow-ga