In addition to the 70 amp big case alternator, some Ford, Mercury, and Lincoln cars had an optional 90 amp big case. An example of this to buy at a parts store is a 1973 Lincoln Town car. Big case alternators used different brackets than small case. So you would need to alter the adjustment bracket. Welding required.
Me personally? I'd go 3G. 2X Rich. Bigger is better. The 3G was designed for higher output and keep the heat under control that is generated by a high charging rate

 

About 1980, when I changed engines, I installed a 105 amp single wire internally regulated GM alternator. As all the others have said you can't have enough amps. Like Orich I had a cabover camper and 2 batteries and it kept them charged without a long drive.

 

Even though I have not compared lately, they've upped the ante slightly over the years. Typical aftermarket replacements for those are now 100 to 105 amp rated. Same unit, higher rating.
The one in my '79 pickup is 105a rated. In the one alternator book I have (BBB brand) they list the older Lincolns as having the 90a version you mention, but later ones call it out as a 100a. So maybe even Ford upped the output over the years?

Not sure about the brackets on other engine families, but that has not been the case in my experience with 302's and 351w's in the past. Straight bolt-on with no modifications required.
Now, in full disclosure mode, I did have to elongate the slotted adjusting hole in my first install (302 w/standard brackets) because I was using my existing belt that was just a tad too long. A slightly shorter belt and I would not even have had to do that.
The next two I converted didn't need even that modification as the belt was already the correct size even with the new alternator.
Example of "standard" 302 brackets I that don't (normally) need modifying: https://www.wildhorses4x4.com/catego...nator+brackets
Maybe that's not the same on the other engine families, but that was my experience. I can see how an adjusting bracket like in the previous pic from orich would need to be modified, however the single pivot point of the lower adjuster on mine allowed a lot of leeway.
Sorry I forgot exactly what engine we were talking about... But if old28's I-6 I think he's probably in good shape for either upgrade.

But totally agree with going 3G instead of large-case 1G these days. I still like the big 1G's, but it's hard to argue with success. Or good things in small packages and clean wiring!

Paul

 

Well I have my headlight relay system installed on to the original wiring harness along with my replacement H4 halogen lens (not Hella). The truck is a 1971 F250 300" 4.9L inline 6 with a stock 60 amp alternator. The head lights are better than stock seal beams, but not what I would expect from the system.
After looking at a test chart of 4 Ford alternator outputs I think it is time to replace the 1G-60 amp alternator with a 3G. The chart reading were as follows:
1G -- 15 amp @ 900 rpm & 60 amp @ 2000 rpm
2G -- 25 amp @ 900 rpm & 75 amp @ 2000 rpm
3G 95 -- 65 amp @ 900 rpm & 101 amp @ 2000 rpm
3G130 - 85 amp @ 900 rpm & 155 amp @ 2000 rpm

I feel that because my truck is pretty bare with Halogen H L, Heater, electric wipers & horn and I cruise around town 90% of the time in the 1500 - 3500 RPM range that I could get by with a
3G-95 amp unit over the 3G-130 amp. Do you guys think the extra 20 amps @ 900 rpm & the extra 54 amps @ 2000 rpm will make a difference in my Halogen HL operation?
I think the 3G95 & 3G130 are not a lot different in price.

 

YES, it will make a difference! As far as price, get one at the Junk yard. Then replace the brush unit (your local auto parts store will carry this). It will go for years. If you feel better about a "new" unit, then replace the front and rear bearings, That's about all that ever wears out in the 3G.

 

More power. Same effort in installing an underpowered unit. You did that already. You don't want to have to do it again for the 3rd time.

 

I found a near new 3G rebuild at the loco junk yard for $23 bucks out the door. Took it to a loco rebuilder for testing out put.
It was all good. No fading of the head light brightness after stopping was what, I liked running dual batteries.
it's all good after that.
Orich

 

You can answer that yourself easily with a volt-meter right now. Lights are brighter with voltage, not amperage. The extra amperage only keeps the system at it's peak voltage when under load.
If your lights are not what you expected with the engine off, the new alternator won't change anything. If your new lights are not what you expected with the engine running, measure voltage at the battery. If you have the expected 14.5v (give or take half a volt) then the higher output alternator is not going to change that either.

If your lights only dim when you turn on other loads, such as the heater, then yes, a better alternator will help. If the light's brightness is not steady, yes a new alternator will help (as long as the wiring is in good shape).
Usually though, with relays in the light system and system voltage at 14.5v, any lack of light is the lamps themselves (or a fault at the wiring) and not the alternator.

Just to be clear, yes I have 130a 3G's on my Broncos, and a 105a 1G on my pickup. So I'm all for bigger and better alternators. If they happen to clean up the wiring and are generally more reliable, those are really nice bonuses.
But if you have sufficient voltage at the battery now and it's steady, a new more powerful alternator is not going to fix dim lights.
To confirm, you can check battery voltage, then check voltage at the light connectors. If there is a measurable drop, something's not right in the wiring even with the relays.

Paul

 

I didn't want to make it sound like I was recommending against changing your alternator out to a more modern one. I still think a 3G is a great all-around upgrade.

I like the flow of your chart and how you broke it down too. Your headlights on low-beam use approx. 7.6a when the system is at 14.5v and about 9a with the engine off, just running on the battery. Generally why you see lights get dimmer at idle and brighter at higher rpm.
With the engine's ignition taking maybe another 3 to 7 amps maybe(?just a swag) you could expect a noticeable increase in the light brightness when you rev the engine up a bit. With a 3G you may not note any change because it's more than capable of handling things even at idle.

So again, I was not advocating staying with the original style. I was simply saying it might not fix sub-par headlights if that's what you're fighting.
Which ones did you get by the way? You said "not Hella" but what brand did you get?

Paul

 

Before I go any further on a 3G install I am going to make sure that all voltages are in the 14.5 range at the battery & on the relay wiring plugs. I should have been a little more clear in the head light operation. They are not going from bright to dim as the alternator rpm go from say 650 to 1500. The headlight say more or less the same but they are not as bright as I think they should be.

I think that Paul (1TonBasecamp) may have hit on what I was also thinking, the problem may be the style of head light lens that I have installed. They are Topgear Autosports 7" that came with standard 55/65 H4 halogen bulbs. I have tried a OSRAM Night Breaker 55/65 and a Hella 80/100 and all three are about the same brightness. The 80/100 H4 Hella bulb should be a lot brighter. As I have learned from this site it is the proper lens construction that controls the pattern & true brightness and not the bulb. I may have to change the lens to the Hella Vision Plus as other have & are happy with to solve my overall light problem.

Thanks to all for the help Tom

 

Be interested to hear what you find on the voltage front. Since it's not dimming down (or not getting brighter?) when the rpm changes, you may already be holding peak voltage at idle. Either that, or the other scenario is that it's not reaching the full 14.5v when running at higher rpm.
But when it really comes down to it, like you said it's more about the lamp itself than the voltage. While you may see a notable difference in brightness between 12v and 14v, it's not like you've opened up a new world or anything. It's just brighter. Does not turn a dim-bulb into an aircraft landing light!

For the record (I think I've mentioned it already though) I'm running my old Hella 7" rounds in my Bronco and love them. But I'm using my old ones because the new ones from a couple of years ago sucked pretty badly. Same part number, same lens fluting configuration, same in every way as far as I could tell. But the new ones had as ****-poor a beam pattern as just about every other round light I'd tried over the years.
If I can't return them for exchange, or fix them myself, I'm just going to throw them away.

My point is try them immediately so there is no question about returning them if they're bad like mine. Generally speaking, most people are as happy with the Hella brand as I am with my old lamps. I hardly ever hear of complaints like mine. So the good news is that if you go with Hella you're more likely to get a good pair than a bad pair.
The other alternative is the Cibié, or it's cousin/clone from Valéo. Same company, bargain price vs full pop. Same lamp from what everyone has said. I'm going to try a set myself. I did a mass-buy about 20 years ago and as far as I know all the people that bought them loved them.
Whichever way you go though, please keep us updated. Enquiring minds need to know!

Paul

 

The 95a is a smaller case, the 130a will actually run cooler in spite of the higher output. Mine came from a 3.0 6 cyl. '94/'95 Windstar which is the larger 130a having 7" mount hole spacing, fit the original brackets and spacer perfectly.

Cibie e-codes are my vote, part #82440. They can be purchased from Daniel Stern Lighting, he has an excellent tech section and really it's the link that is missing from this thread-Daniel Stern Lighting Consultancy and Supply

 

Minor points:

• I agree with most of the postings above. However, I think some are jumping to upgraded bulbs and housings just a little too soon for budget-minded restorers.
• Light output goes up exponentially with voltage, assuming unlimited amps are available. Higher volts is better.
• So, larger wire on both the positive, AND the negative wires are needed to avoid resistance. Running down the road warm, you should be getting 13.6-14.2 volts to the headlights. Remember the resistance in the fuse, it is part of the circuit.
• Use the test method called "voltage drop" to find resistance, since ohm-readings won't work in a powered, loaded system.
• Test voltage between the low-beam-positive-connection to battery-terminal-negative: should give you no less than 0.2 volts below battery-positive. Otherwise your resistance is too high. Small resistance cuts the light a lot.
• Grounding is as important as feeding the light-beast. Good connection technique, maybe some solder, is required. I did both and covered with 'double-wall' shrink tube to support the connections. That ground circuit can go to the sheet metal, but then that needs to get back to battery-negative. Don't add grounds, fix the factory locations first.
• Especially in cold climates, double belts are needed for the large-case 90+ amp units. This is mostly a squeal-issue, and only at startup. But belt life and reliability may be important for you. I have double belts, and still would get a squeal after it had been sitting for a week. If you can run a 3G, it will give you a better voltage profile, and low-RPM amp production.

Mine has 'normal' headlights, 10gu wire all the way around, relays, and the 130 amp 3G alternator. Very happy, and saved the money for other things. Light-output is great, and similar to other new vehicles.

AFTER all this is done, if you still are needing more light, then sure, open your wallet and get the high-quality H4 setups. The work above will bring out the best from your purchase.

The cut-off beam pattern puts more light in a useful band for highway and traffic use. Country and off-highway users might not like the cut-off feature.
Remember to use the bulb that was intended for the reflector housing. Mixing will give you coverage problems.

 

Jon Richards -- Thanks for the 3G information. Are you saying that a 3G 130 anp from a 3.0L 6 cylinder from a 94-95 Windstar will bolt right into my 1971 300" 4.9L 60 amp alternator bracket?

1972-3/4 ton -- I will spend some time after the holidays to make sure voltage and grounds are as they should be and that the relay harness is operating correctly.

1TonBasecamp -- Like I said yesterday, I need to check out the full system before I move forward on new Hella Vision Plus lens. After I know the light system is correct and I have the relay harness in place, I am going to pop the old seal beams back in just to see if it makes a difference in them, I would like to know.

 

My Ranger has a 302ci so I'm not entirely certain about your space constraints or brackets, but I was running a 1G and the large case 3G with 7" mount hole spacing (94/95 Windstar, and some Taurus and Sables) practically fell into place. The only thing I did was clock the rear half of the case to line up the connectors where I wanted but it is super easy to do and isn't necessary.

I don't have a 4.9L to check, but well, it'll bolt right in