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Discussion Starter #1 (Edited)
I converted the headlights on my 67 GTO over to the H4 setup. I did this on my 70 Vette and it was a game changer, so it was a no-brainer to do on the goat. I bought the bulb kit from OPGI, yes it was $200, and yes, it's worth $200 for me to light the road up like July 4th, when I'm racing through the Pine Barrens at 3am.

Anywho... On the Vette, I used a relay system to bypass the original switch and wires, and send the full voltage/ amperage of the alternator to the headlights. I made my own relay harness (which does not affect the OEM harness at all), because there was only one available at the time and it was backordered.

On the GTO, I searched for others experience and found "lamp advice" but no wiring recommendations. So I decided to just plug in the H4's and go. They worked, but like crap.

I read the voltage at the headlamp socket and it was barely 10 volts. And, I don't see the 55 year old switch handling this for much too long. Yes, you will need to get a hole saw and enlarge the original headlight buckets, but of course, if you go back to a sealed beam, they will then still work.

I'm sure that most of you have already found their way around the dim lighting, but if not, this is definitely the way to go. I have a 2020 luxury SUV, and the GTO headlights now FAR surpass the SUVs output and visibility, which of course equals safety and fun for me!

Here's what I used:

There is a ready made relay harness available, but it's almost $200. You can make your own for well under $50. You'll just need two relays, about 20' of 14ga wire, and four ceramic H4 adapters. CAUTION!!!! The kits claim that you need to cut a 2" hole in the buckets, but it's more like 3"! When the install is done, I'll post pictures of the stuff.

On a side not... I've long suspected that GTO's where the rarest gem in the muscle car world (and I've lost many arguments at the car shows by claiming it), but WOW, there's a dramatic difference between the GTO crowd and the Vette crowd. Information is so much harder to find for the GTO... however, at least I don't have to wade through mountains of misinformation (which was a big issue with the Vette guys).

What I'm getting at is, I apologize if I've been making any redundant posts in here lately, but in the off chance that future generations are interested in preserving/ updating these cars, I'm trying to document some of the things that help to keep the car stock in appearance (reversible updates) but modernize its abilities and reliability. I'm not a restomod fan, but I do strongly believe in better brakes, suspension, lighting, and reliability.
 

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I converted the headlights on my 67 GTO over to the H4 setup. I did this on my 70 Vette and it was a game changer, so it was a no-brainer to do on the goat. I bought the bulb kit from OPGI, yes it was $200, and yes, it's worth $200 for me to light the road up like July 4th, when I'm racing through the Pine Barrens at 3am.
I put these in all 4 buckets on my '69. Man what a difference! With these things, at night I can see all the way into next week.

H4 Bulbs
H4 Housings

Just a wee bit of customizing was required on the high beam side. The slots in the buckets for the locator tabs are different between high beams and low beams, and these housings are intended for low beam only. It was an easy fix though. Since the tabs on the new housings are on a separate ring of sheet metal and not part of the glass like they are on regular bulbs, all I had to do was snip off the one tab that didn't line up with the bucket using a pair of sheet metal shears. Also the high beam connector in the wiring harness only has two terminals, but it still connects just fine to the bulb. I wrapped insulating tape around the exposed terminal on the bulb to cover it.

139600

139601

139602
 

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Discussion Starter #3
I put these in all 4 buckets on my '69. Man what a difference! With these things, at night I can see all the way into next week.

H4 Bulbs
H4 Housings

Just a wee bit of customizing was required on the high beam side. The slots in the buckets for the locator tabs are different between high beams and low beams, and these housings are intended for low beam only. It was an easy fix though. Since the tabs on the new housings are on a separate ring of sheet metal and not part of the glass like they are on regular bulbs, all I had to do was snip off the one tab that didn't line up with the bucket using a pair of sheet metal shears. Also the high beam connector in the wiring harness only has two terminals, but it still connects just fine to the bulb. I wrapped insulating tape around the exposed terminal on the bulb to cover it.
WOW!!!! On the Vette I used Hella housings and I was floored by the improvement. As I mentioned, the GTO had A LOT less tech info out there, so I wound up with the Delta kit... but it looks like I couldv'e gone much cheaper if I tried to source the lenses and bulbs separately. In any event, the improvement was well worth any cost. For the record, NAPA and Amazon don't list a headkight switch for a GTO! You have to say that it's a LEMANS.

The switch will fail the with the H4's, unless relays are used.

I wouldn't imagine that your LED's needed a relay kit. Did they? My Grand CHerokke has state of the art LED's, but they have NOTHING on my Vette H4's.
 

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Discussion Starter #6
I put these in all 4 buckets on my '69. Man what a difference! With these things, at night I can see all the way into next week.

H4 Bulbs
H4 Housings

Just a wee bit of customizing was required on the high beam side. The slots in the buckets for the locator tabs are different between high beams and low beams, and these housings are intended for low beam only. It was an easy fix though. Since the tabs on the new housings are on a separate ring of sheet metal and not part of the glass like they are on regular bulbs, all I had to do was snip off the one tab that didn't line up with the bucket using a pair of sheet metal shears. Also the high beam connector in the wiring harness only has two terminals, but it still connects just fine to the bulb. I wrapped insulating tape around the exposed terminal on the bulb to cover it.

View attachment 139600
View attachment 139601
View attachment 139602
Last night, I finished up my H4 relay harness. I was going to keep halogen bulbs, but I ordered up four of these beam techs, so that I could drop some temperature. I did check the volts at the headlights, before and after. It was only about 10-11 before, and now it's 14.4, so with the LED's, it should be screaming.

I also wired it Low X4, and High X4... by adding the low beam terminal to the lower liight, so now all four headlights each run a single filament on low beam, and they will each run eight filaments on high! Anxious to see it with LED's
 

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1967 Lemans 1967 GTO parts car
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I guess i spent to many nights following a little red rectangle through the woods with no lights on that I don't give headlights a thought. My high beams are used only to signal people. That bright light just kills my night vision. The time for bright lights in the city.
 

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Discussion Starter #8
I guess i spent to many nights following a little red rectangle through the woods with no lights on that I don't give headlights a thought. My high beams are used only to signal people. That bright light just kills my night vision. The time for bright lights in the city.
It has a lot to do with where you live, too. I'm in South Jersey, in the heart of the Pine Barrens and NJ's (astonishingly plentiful) back woods, country roads. There are no lights at all... and it's dark at 4:45 pm. So if you're blasting down a 15 foot wide road, at 9pm, with solid woods on both sides, no shoulder, during deer season, you want it lit like mardi gras!
 

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It doesnt matter the conditions to me. I lived in the Carolinas, Ohio, Oklahoma, Missouri, Florida, Arizona, and Iceland. Bright lights always made the dark darker. I have been on many roads that you are describing. Its great when they are paved. You will see the deer when it hits your car and sometimes that is the best option. I think alot of it has to do with what you are use to.I have always ran around in low light no light conditions. We always snuck out to go fishing or just goof off.You just have to keep an eye out for snakes and gators..Did the same in the military they weren't big on well lit working environments. Everyone is different. If it works for you go with it
 

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Discussion Starter #10
Agreed. I'm retired LE and military, and there was never any light, but I love it now that I can get it.
 

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I converted the headlights on my 67 GTO over to the H4 setup. I did this on my 70 Vette and it was a game changer, so it was a no-brainer to do on the goat. I bought the bulb kit from OPGI, yes it was $200, and yes, it's worth $200 for me to light the road up like July 4th, when I'm racing through the Pine Barrens at 3am.

Anywho... On the Vette, I used a relay system to bypass the original switch and wires, and send the full voltage/ amperage of the alternator to the headlights. I made my own relay harness (which does not affect the OEM harness at all), because there was only one available at the time and it was backordered.

On the GTO, I searched for others experience and found "lamp advice" but no wiring recommendations. So I decided to just plug in the H4's and go. They worked, but like crap.

I read the voltage at the headlamp socket and it was barely 10 volts. And, I don't see the 55 year old switch handling this for much too long. Yes, you will need to get a hole saw and enlarge the original headlight buckets, but of course, if you go back to a sealed beam, they will then still work.

I'm sure that most of you have already found their way around the dim lighting, but if not, this is definitely the way to go. I have a 2020 luxury SUV, and the GTO headlights now FAR surpass the SUVs output and visibility, which of course equals safety and fun for me!

Here's what I used:

There is a ready made relay harness available, but it's almost $200. You can make your own for well under $50. You'll just need two relays, about 20' of 14ga wire, and four ceramic H4 adapters. CAUTION!!!! The kits claim that you need to cut a 2" hole in the buckets, but it's more like 3"! When the install is done, I'll post pictures of the stuff.

On a side not... I've long suspected that GTO's where the rarest gem in the muscle car world (and I've lost many arguments at the car shows by claiming it), but WOW, there's a dramatic difference between the GTO crowd and the Vette crowd. Information is so much harder to find for the GTO... however, at least I don't have to wade through mountains of misinformation (which was a big issue with the Vette guys).

What I'm getting at is, I apologize if I've been making any redundant posts in here lately, but in the off chance that future generations are interested in preserving/ updating these cars, I'm trying to document some of the things that help to keep the car stock in appearance (reversible updates) but modernize its abilities and reliability. I'm not a restomod fan, but I do strongly believe in better brakes, suspension, lighting, and reliability.
I'm curious to know why two relays are required. Assuming one on high beam the other on low beam. I installed H4 low beams late fall last year, will do high beams this spring no relay but my frontrunning lights only function as signsls now, tail lights function properly. No front running lights with first stop in the light switch. That a symptom do you think of a failed or soon to fail switch. Should mention switch is new.
 

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Discussion Starter #13
Yes you need two relays.... One for high and one for low. If you dont use relays with H4's, the amps will fry your OEM switch... So, it's either gone or going.
 

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Discussion Starter #15
m not sure about H4s, but i just put the 575 from dapper lighting and i am pretty stoked how they came out.
I did the H4 Hella conversion, a relay harness, and then upgrade to the LED H4's that Bear suggested. Now I have a full 14 volts, going to high quality LEDS, in a Hella Glass lens. It's amazing... Lights the road up like daytime! Without the relays, the lights only got 9 volts and then flickered and died when the switch heated up.

BTW... The factory configuration is Two filaments in the upper Low/ High beams, and one filaemt in the lower High Beam only. While making the the relay harness, I added the second filament into the lower bulb, so now I have 8 filaments vs. the oem 6.
 

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I did the H4 Hella conversion, a relay harness, and then upgrade to the LED H4's that Bear suggested. Now I have a full 14 volts, going to high quality LEDS, in a Hella Glass lens. It's amazing... Lights the road up like daytime! Without the relays, the lights only got 9 volts and then flickered and died when the switch heated up.

BTW... The factory configuration is Two filaments in the upper Low/ High beams, and one filaemt in the lower High Beam only. While making the the relay harness, I added the second filament into the lower bulb, so now I have 8 filaments vs. the oem 6.
Thank you for your speedy response Darkness. Will definitely follow your advise when spring rolls around. If I had heated storage I'd be on it now.
 

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Discussion Starter #17
I recommend the harness, because although the LED's draw less power than Halogens, and are less likely to fry the wire or switch, you're still not getting full voltage and not using the high beam dual filaments, unless you use relays and a custom harness. That being said, bear seems to be running LEDs without issue.
 

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I recommend the harness, because although the LED's draw less power than Halogens, and are less likely to fry the wire or switch, you're still not getting full voltage and not using the high beam dual filaments, unless you use relays and a custom harness. That being said, bear seems to be running LEDs without issue.
Since my last post I looked at the other two bulbs to go in in the spring and they're halogens. I'm told I can factory stuff without relays. Thoughts,?
 

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Discussion Starter #19
Since my last post I looked at the other two bulbs to go in in the spring and they're halogens. I'm told I can factory stuff without relays. Thoughts,?
It's very subjective. If you go to the Corvette forum and ask the same question, they will insist that it is the worst idea on Earth, to consider an H4 swap without relays. They're both GM's with a four-light system, so what's the difference?

Since my last resto was a Vette and now I'm doing a GTO, I found it odd that the same system would have a different mentality. I think it centers around the fact that when a Corvette headlight switch burns up, you have to take the entire car apart to change it.

Any traditional filament bulbs brightness will increase with voltage. The bulb will probably light down at 6 volts and then brighten all the way up to 18 volts. So question number one is, do you want bright lights or dim ones? Since you're not happy with the OEM T3's, I'll assume that you want bright.

Question two is component matching. Putting an 850 double pumper and high-flow intake, on a car with low compression smog heads and single 1.75" exhaust, will not yeild benefits, because everything needs to work together. Halogen H4 bulbs draw a lot more power than a circuit from the 60's was designed to handle, and even if they could handle it new, now they're 50 years old.

Finally, can it be done? Yes. You can smoke two packs a day and live to be 100, but that's more luck than effort. As I mentioned, I too, was surprised that the GTO retail community, didn't mandate relays for the H4's, so like you, I cut the corner. And... IMMEDIATELY following installation:
  1. My headlights were barely brighter than the T3's (if at all), because the stock wiring and switch was only able to pass 9 of the 14.4 volts that my car was capable of.
  2. My headlights would stay on for about 10 minutes and then get hot and shut off.
  3. Within a week my switch burnt up.
So, it's a lot of work to install H4's in OEM buckets. I wouldnt bother unless I was going to get the full voltage and add the extra two high-beam filaments, that you can only activate with a custom wire harness. The harness would cost less than $25 to make and you can do it while sitting on the couch watching the Munsters.

The only exception to any of this advice is that if you use LED (like bear), they will draw much less power than halogens and also be brighter, so you could beat the system... depending upon the condition of your system. However, for another $25 and hour worth of work, you would be go from a 6 filament system to an 8 filament system and then increasing the overall brightness by about 30%.
 

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It's very subjective. If you go to the Corvette forum and ask the same question, they will insist that it is the worst idea on Earth, to consider an H4 swap without relays. They're both GM's with a four-light system, so what's the difference?

Since my last resto was a Vette and now I'm doing a GTO, I found it odd that the same system would have a different mentality. I think it centers around the fact that when a Corvette headlight switch burns up, you have to take the entire car apart to change it.

Any traditional filament bulbs brightness will increase with voltage. The bulb will probably light down at 6 volts and then brighten all the way up to 18 volts. So question number one is, do you want bright lights or dim ones? Since you're not happy with the OEM T3's, I'll assume that you want bright.

Question two is component matching. Putting an 850 double pumper and high-flow intake, on a car with low compression smog heads and single 1.75" exhaust, will not yeild benefits, because everything needs to work together. Halogen H4 bulbs draw a lot more power than a circuit from the 60's was designed to handle, and even if they could handle it new, now they're 50 years old.

Finally, can it be done? Yes. You can smoke two packs a day and live to be 100, but that's more luck than effort. As I mentioned, I too, was surprised that the GTO retail community, didn't mandate relays for the H4's, so like you, I cut the corner. And... IMMEDIATELY following installation:
  1. My headlights were barely brighter than the T3's (if at all), because the stock wiring and switch was only able to pass 9 of the 14.4 volts that my car was capable of.
  2. My headlights would stay on for about 10 minutes and then get hot and shut off.
  3. Within a week my switch burnt up.
So, it's a lot of work to install H4's in OEM buckets. I wouldnt bother unless I was going to get the full voltage and add the extra two high-beam filaments, that you can only activate with a custom wire harness. The harness would cost less than $25 to make and you can do it while sitting on the couch watching the Munsters.

The only exception to any of this advice is that if you use LED (like bear), they will draw much less power than halogens and also be brighter, so you could beat the system... depending upon the condition of your system. However, for another $25 and hour worth of work, you would be go from a 6 filament system to an 8 filament system and then increasing the overall brightness by about 30%.
Sold my friend. Two relays going in in the fall.
 
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