If you are converting a wood stock, hinged floor plate to a detachable mag you will need to get new trigger guard/bottom metal assembly and a clip. You will have to inlet the stock for the clip release buttons. You may also have to widen out the magazine well in the stock if the clip fits too tightly.
other option is the Kwik Klip if this was a long action rifle. Take your time, mark the cuts carefully, use a small router and hand file to clean up. Don't take out too much wood or your job will not look so nice. You may want to angle or profile the relief cuts so that it looks nicer.