There are several things you can do to improve the brakes on A65's:-
- get the shoes relined with a modern compound such as 2520V or 2420V available at Vintage Brake, see This Link
. These compounds are much better than the old Ferrodo or other shoes. Its best to have the shoes and drums arced to ensure full contact.
- ensure the brake cable takes to the shortest route to the drum and has the least number of curves as these sap power. Use a Teflon lined outer cable as sold by Venhill, these help improve pulling power.
- use a brake lever with a 7/8 pivot, that's the distance from the lever pivot to the cable barrel. Many levers use 1 1/16 pivot lengths which is less efficient
- before tightening the drum axle centre bolt and pivot, pull the brake lever hard and hold it tight with a cable tie, then tighten the bolts. This should help ensure the shoes are centered.
Each of the changes above will bring an improvement of maybe 10 to 15%, so taken together you could end up with a very good brake.