Here is some info from Bob Wilson's site on the subject:
WILSON WELDING HUB INSTALLATION FACT SHEET
The hubs you have received have a five-lug bolt pattern of YOUR choice. Before installation, your drums must also be drilled with the same pattern. You have three choices: 1) Ship them to us and we will drill them for $25 per hub plus shipping. 2) Have them drilled by a local machine shop, 3) Follow the steps below and do it yourself. You will need a Wilson Welding drill bushing bolt guide ($5.95 plus $3.00 packing, shipping), a good drill press (not a hand held drill), a ¼ inch, 3/8 inch and ½ inch drill bits.
DO IT YOURSELF DRILLING YOUR DRUMS
Step 1 – Remove the Buick hub from the finned Buick drum.
Step 2 – Lay the drum, outer side up, on a flat surface. Temporarily insert fully the new hub, small bearing hole upward, into the hole of the Buick drum. Hand thread the drill bushing bolt into any one of the threaded holes of the new hub until it lightly touches the drum surface. Locate the hub in the drum to insure maximum distance from the already existing stock holes present in the drum. Drill a single ¼ inch hole in the drum using the drill-bushing bolt as a guide. This needs to be done with a drill press, not a hand held drill.
Step 3 – Remove bolt from the hub. Remove the hub from the drum. Again, using a good drill press, enlarge the ¼ inch hole to ½ inch. Step drilling is the best approach. Graduate from ¼ to 3/8 to ½ inch.
Step 4 – Reinsert the hub into the drum as before and insert a ½-20 X 2 inch grade 8 socket head cap screw from the inside of the drum, through the drum, into one of the threaded hub holes. Tighten lightly. This grade 8 bolt will stabilize the hub in the drum and will allow you to drill the last four holes into the drum. One at a time, insert the drill-bushing bolt into each of the four remaining drilled holes in the hub and drill a ¼ inch hole.
Step 5 – Remove the grade 8 bolt. Remove the hub from the drum. Enlarge the four – ¼ inch holes to ½ inch with your drill press. Again, step drilling is the best approach. Note: NEVER ATTEMPT TO USE THE NEW HUB AS A DRILLING GUIDE WITHOUT THE DRILL BUSHING BOLT. THE ½ INCH DRILL BIT WILL RUIN THE MACHINED THREADS IN YOUR NEW HUB.
INSTALLATION OF THE HUB TO YOUR DRILLED DRUMS
With your drums drilled, you need five grade 8 socket head cap screws, ½-20 X 2 inches long, the included round flange with five holes, your drums and your new hubs. With the new hub on the outside of the Buick brake drum, the five bolts are inserted from the inside of the drum. First place the included round flange inside the brake drum. Insert the five bolts through the flange / through the drum surface and threaded into the hub from the back side. After all five bolts are threaded and tightened for the final assembly, tack weld the grade 8 bolt heads onto the flange. This is critical for your safety. If you do not secure the bolt head to the flange, you are asking for trouble. (Be certain that all your painting, polishing, detailing has been finished before final welding) Grade 8 bolts MUST be used. A grade 8 Bolt has 5 marks on the head surface. After FINAL hub/drum assembly, the drum brake surface must be trued on a brake lathe before mounting. The bearing races must be installed before the hub/drum assembly can be trued.
WHEEL BEARING INSTALLATION
Before mounting your wheels to the drums, you have to CORRECTLY install your bearing races, bearings and dust seals. If you think a lot is riding on your tires, you have just as much riding on your wheel bearings. If you are not sure how to pack your bearings, how to install the bearing races and know when to stop tightening the spindle nut, have a pro do it. YOU MEAN THE BEARINGS DO NOT COME GREASED FROM THE FACTORY ?????? To install the dust cap, place a short length of 2 inch pipe on the outer lip of the dust cap. Hammer on the pipe, not directly on the dust cap.
BOB WILSON: 214-662-9483
I would call Bob and tell him what you have and he can steer you. Bob is a super nice guy and has a lot of parts on his website that might make the job easier for you.
Don
