I recomend two restoration books (there are others):
Mustang Restoration Handbook, by Don Taylor and Tom Wilson, ISBN 0-89586-402-9
How To Restore Your Mustang, by Larry Dobbs and Donald Farr, ISBN 0-96249-084-9
Try National Parts Depot www.npdlinks.com
- or your other favorite Mustang parts store, Amazon, or www.abebooks.com
Get a copy of the 1970 Mustang Shop Manual.
I also recomend www.eastwood.com
for special welding tools.
The best advice I can give is to make measurements of your tooling holes based on the info in the Shop Manual, and do one side at a time.