Just go to a good parts store and ask for the longest warranty timing set. That will be almost as good as oem. Or you could go to ford and get the oem timing set.

 

Just go to Napa or CarQuest or Advance or whatever part store is in your area and ask for a timing chain/gear set for your year/engine Bronco. Should be a double roller, and they'll hook you up. Simple as pie to swap out once your in there. Line the dots up so its at TDC, pull em off, and slap the new ones on. I swapped mine, and my old chain had well over an inch of play in it. New chain is tight as a drum (a little slack, but thats normal) and the truck purrs like a kitten with MSD cap/rotor, Blaster 3 coil, FMS wires, Autolites gapped to .55, timing set to 13 degrees, and vacuum diaphragm tuned in.

Just swap the gears. You probably wont ever have to do it again.

 

Thanks everyone for the help. I bought a used timing light off eBay and finally got to test the Bronco on the highway after setting the timing at 12 BTDC. The difference is absoultely unbelieveable. The engine no longer runs like it is full of cold molases. If the home hardwood flooring arrives before the next holiday weekend I'll install it to keep peace but, hopefully I'll replace the timing chain and gears that weekend. I had spark and compression together and fuel arriving late. Now I have spark and fuel arriving closer together and compression a little late. I can't wait for a new timing set and get them all together. I am hearing preferences of double roller chain. I guess any brand will outlast the rest of the 172K engine.

 

Timing can make a huge difference. I once bought an old 74 Buick Regal for $400, just for transportation. It had a big 455. It seemed pretty sluggish for having such a big motor in a medium sized car. I power timed it (advanced timing as far as I could without causing the motor to ping) and suddenly that car would burn rubber for three city blocks and topped out around 150 mph with its 2.73 gears. Not bad for a $400 transpo car.

My Bronco runs fine but I'm gonna try the 12 degree setting to see what happens. My timing chain and gears have only around 40K on them.

 

Thanks guys for the help, especially MatthewC for encouraging me to replace the timing chain. The difference is drap-jaw, suck you back in the seat then big grin amazing. There are tips scattered everywhere and many years back here in FTE. I have come to add some also now that I am a one timing chain expert...Ha! Here are a few:
First check the chain for slack per Haynes manual. Replacement hints:
1. Take your time, don't rush it or have a deadline.
2. Get a Haynes manual.
3. Lay a board across the fenders (2X4) and use a wratchet strap to support the A/C and P/S assembly out of the way and make reassembly really easy.
4.. Get big cardboard, draw rough sketch of W/P, T/C cover etc and mark bolt locations, punch holes and stick a bolt in in each time you remove one.
5. Removing water pump bolts is the most difficult part. Don't break the bolts off but use a torch on the block and heat slowly and gently about 30 seconds then rock the bolt back and forth 30 seconds. Repeat for very long time if needed.
6.. After the water pump is off, clean up the coolant spills then drain the oil.
7. Harmonic balancer bolt is 1 5/16". O'reillys has the socket. Do not pull on outside of harmonic balancer.
Remove the bolt completely before removing the HB. Leaving a few threads in and dropping the HB damages the threads. Tap and die are nowhere to be found on a weekend. A "bolt house" or fasterner supply will have the 5/8-18 taper tap to fix the crankshaft threads.
8. Air tools are not needed. If you have auto. transmission, to remove crank bolt, try hitting your breaker bar with a hammer. If not successful, PULL DISTRIBUTOR WIRE, stick the end of the breaker bar in the square hole in the passenger side frame and on the crank bolt. Turn key to start and back off as fast as possible. Try hammer on the breaker bar and if needed, repeat the starter method just a little bit.
9. When timng cover is off, stuff rags down in the oil pan to catch trash.
10. If your oil pan gasket is rubber with metal in it, do not cut it, just leave it. Fel-Pro gasket kit includes RTV for the oil pan gasket and thread lock for the cam bolt. I used Prematex Tack and Sealing on everything else, timing cover, water pump, thermostat and all their bolt threads that screwed into the block. Use 5/16 tap to clean all the holes. Stick the gaskets to the timing cover, thermostat and water pump several hours before assembly.
10. After cleaning all mating surfaces thouroughly, use the reast of the all-thread and rag to get the little bit of trash out of the oil pan. You did break a timing cover bolt, didn't you? And made a replacement with 5/16 all-thread? Anyway I didn't want trash any trash getting on the oil pump screen.
11. Rinse the pan. Pour a couple of quarts of used oil off the top into something small. With oil plug still out, pour the oil in beside the crankshaft to rinse the pan of any trash I could not see.
12. The original chain was double roller, sprockets were steel (magnet stuck) no plastic coating was visible to me. Teeth were feeling pointed. Chain deflection was only about 3/8" but new Cloyes set was almost nothing it fit so well.
13. While at it, new water pump, radiator cap and thermostat, hoses and belt, depending on age. Also, oil drain plug gasket is 9/16".
14. BUILT FORD TOUGH observations...172,000 miles and very little slack, I was disappointed I had decided to do this but after driving it the results are far, far, far better than expected in performance. It was well worth the effort.
15. Mobil clean. I switchhed the oil to Mobil Clean High Milage the last time and was surprised to find this old engine so clean in the pan and timing chain area. The drained oil was the nastiest stuff I have ever seen. Worse than even a nasty diesel oil. It does clean.
16. Check the timing.
Obviously all our Broncos are aging, as I am. This fixed the sluggish engine, at least on the Bronco.