Technical Ford 390 Distributor Gear Question

I just bought a '63 T-Bird with what looks like a rebuilt 390 from a '61 Ford (if the block and intake numbers are any guide). The bores look new, but when I bought it, it surged really badly at idle. Anyway, I found that the distributor was just worn out in every way, so I bought a new one from a parts store.

The parts store distributor has what looks like a normal gear for an iron cam, but the old worn out distributor had a light colored gear with what looks like copper underneath. A magnet sticks to the gear, but without any information on the rebuild (the previous owner is deceased), I'm a little nervous about running a stock cam gear. I can see the #5 lifters from the distributor opening, and it does NOT have a roller cam, so I'm a little stumped. I've run the new distributor for probably an hour or so, and the gears are starting to wear into each other, but I see nothing particularly alarming.

The first picture is just the new cam gear, the second and third ones are from the old distributor, and the last one is down into the engine. I'm sorry, but the first and last pictures aren't too helpful. Anyone have any ideas here? I've never owned anything with an FE... Thanks!

Aaron

 

The Hamb FE Ford gurus will arrive shortly and get you figured out.....

 

The old gear appears to be a nickel plated deal, maybe hard chromed. Was it on an Autolite distributor?

 

I don't believe that the factory gear was bronze but they were and still are available. I still feel that the cast iron gear is appropriate. If it's hard steel, throw it away. If in doubt, swap the old gear.

Sent from my XT1650 using The H.A.M.B. mobile app

 

Yeah, the distributor in it was an Autolite, but I can't imagine this gear was original.

 

Agreed that if you have any second thoughts , reuse your old gear . It should fit and work fine as frog hair .

 

Yes, but that gear doesn't look like it is worn very much in the pics, just through the plating that is on it.

 

Hey, one more thing if you are running points and a vacuum advance. The point plate in the distributor moves in an arc when the vacuum canister pulls on it, that actually changes the point gap a lot. Just something to be aware of when setting points/dwell.

 

If the new distributor has a Chinese condenser be prepared for a failure. 2 went out on me before I replaced everything with a Pertronics ll. If you were happy with how it was running I would install the old condenser in the new distributor.

 

Measure the dimension accurately for correct specification between distributor housing flange and the bottom machined surface of the gear with the shaft extended down before using, one thing I discovered in the course of the Great Counterfeit Y Block Distributor Scandal is that the tolerances must be held very closely in terms of endplay and locating the distributor gear.

For whatever reason replacement gears are all slightly different in their dimensions, and, so is the location of the roll pin hole on them. A replacement gear then, requires locating and drilling a new hole on the shaft. Not saying that's what happened here, but I wouldn't want to risk it.