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10/15/2013 6:19 AM  #1

Conversion H4 extreme

After driving in the evening a road without roadlights, it occured to me that the headlight of my 65 Mustang could be better. I had already replaced my R2 duplo with a R2 halogen. Also the horizontal cut off line between dark and light and at the 15 degrees angle was not tight. When turning my headlight adjuster screw, the feeling was not firm. So it was time to order new headlights, headlightbuckets and headlight adjustable screws.

After reading reviews on the internet of 7” headlights it would be a Hella 235991 or a Cibie 82440. The Cibie had a better spreading of the light, and the Hella 239551 is not for sale here in The Netherlands. (edit 17-12-2013:they can be special ordered via Hella dealers, what can take a few days)

After the parts came in I started with the installation.
The old headlight adjusters had more play in the ‘notch’ in the head than the new ones. On the drivers side there were headlight adjusters installed I’ve never seen in a Mustang.


The Cibie headlight had also almost the same sizes of the old Lucas headlights. A little bit higher, but fits without problems in the bucket.

I noticed that the Cibié had a thin narrow protrusion (for positioning) compared to the Lucas headlight. This also appears to be placing the headlight in the narrow ledge of the headlight holder more difficult.

The new headlight bucket differs slightly from the old one. The three curved tabs where the screws for the headlight ring come in, lie with the new deeper so the old screws were just too short to tighten the ring. New screw with the right thickness and narrow head were quite difficult to find. Most of the screws had a head that was too thick for the hole on the headlight ring.

The new H4 Philips Xtreme +100% bulbs were a great improvement to the old R2 duplo halogen bulbs.

Last edited by RonNL (12/17/2013 6:23 AM)


10/26/2013 4:35 PM  #2

Re: Conversion H4 extreme

I would also recomend putting a relay harness on you're headlight circut this will take the load off the switch and make sure that you have Full voltage going to the headlight i did this and it make a world of differnce i also did the headlight swap like you did.


10/26/2013 10:30 PM  #3

Re: Conversion H4 extreme

Part number on that headlight bucket is for a 67.  I wonder if that is why it was different?

Money you enjoy wasting is NOT wasted money... unless your wife finds out.

10/27/2013 4:22 AM  #4

Re: Conversion H4 extreme


I have all improvements done last year in steps.
First, replaced R2 Duplo to R2 Halogen (was an improvement),
Then installed the relay harness (the light became better),
Now the H4 headlights with the Philips extreme + 100%. (the biggest improvement!)

The R2 bulb and R2 halogen are both 40/45 watt, what doesn't affect the current in the light switch. The amp is the same for both. But the H4 is 55/60 watt, what can result in blinking lights with the old lightswitch. So I had to install the relay harness to prevent blinking lights or other problems. I also put a relay for the horns, to prevent 'smoky' steering.

These extreme lamps emit more light than standard H4 bulb. About the lifetime I can not say anything.

R2 Halogen and the R2 Duplo bulb

Last edited by RonNL (10/27/2013 5:25 AM)

     Thread Starter

10/27/2013 5:14 AM  #5

Re: Conversion H4 extreme

Hi Steve,
I received two buckets. When I compared them with my old (1965) one, there was one that was different. It had not the three curved tabs for positioning the headlight  It had position ‘tabs’, but on different places and different shape. They had both code C7ZB-47-A  in the bucket, what for a correct 1965 model should begin with C5Z…, and the different one had also RH in the bucket. The 1965/66 models had for both sides the same bucket. The 1967/68 model had a difference between the left and right handed bucket.  Reading the label on the packaging there  was one for 65 (however coded C7.., maybe the China aftermarket stuff )  and one for 67. The wrong coded 1965 bucket fits well with a little bit longer screws. But the 67 I returned and will be replaced with the right 1965. Maybe the new one has the correct C5 code.

edit: the new 1965 headlight had also a C7ZB-47-A code inside and fits well.

Left the 67 bucket, at right the 65.

The 1965 bucket.

The 1967 bucket.

Last edited by RonNL (12/17/2013 6:24 AM)

     Thread Starter

12/15/2013 5:49 PM  #6

Re: Conversion H4 extreme

Did you have problems keeping the Cibie headlight sitting firm and square in the headlight bucket.  Those sheetmetal locating tabs were too thin to keep the light from falling out of the notches on one side or the other.  Here is what I had to do with mine to make them seat firmly. 

JB Weld putty and a dremal tool.  I folded the tabs inward a bit, then drilled two holes in each of them to hold on to the epoxy putty.  Then I formed the putty, stuck it over the tabs, let it cure then trimmed them with the Dremel tool.

Last edited by boomyal (12/15/2013 5:52 PM)


12/15/2013 6:09 PM  #7

Re: Conversion H4 extreme

Then I constructed a new back feed harness using all 12 ga wires. In other words I fed the headlight signal to the relays thru one of the original bulb sockets then ran the new 12 ga wire from the relays back out to each headlight. So constructed, I did not have to cut into the factory wiring harness.

Then I made a bracket to mount the relays on and sandwiched the bracket behind the starter solenoid using the original solenoid bracket holes and screws.   

I am using Narva 100/90w bulbs (not for use in Europe, or probably the USA either).  Ask me how bright the headlights are now!  The Cibies were not cheap and not widely available but they are far and away the best seal beam replacements.  I used to use them back in the '70's when all you could get were regular tungsten seal beams.  They were a bit pricey back then but now that not very many cars can use them, they are at a real premium.

Last edited by boomyal (12/15/2013 6:18 PM)


12/17/2013 6:18 AM  #8

Re: Conversion H4 extreme

Nice job with the weld putty! Looks firm.
I had folded the tabs inwards as much as I could. When the headlights were on its place, I put the ring around it, still pushing the headlight firmly in position, and tighten the screws. The headlights remained in place even after having driven over very bumpy roads.

I also installed a harness complete with relais. The light was becoming brighter and I was able to use the H4 lamps.The complete harness set was offered by someone who rebuilds complete Mustangs, and knows a lot about it. It was plug and play without cutting.

I read that you are using 100/90 watt bulbs. Are you not afraid of melting headlights or connectors. I've seen and read about this when using these strong bulbs. I know that Hella is offering extra strong headlights for using stronger bulbs.

Last edited by RonNL (12/17/2013 6:28 AM)

     Thread Starter

12/17/2013 8:04 PM  #9

Re: Conversion H4 extreme

RonNL wrote:

  .....I read that you are using 100/90 watt bulbs. Are you not afraid of melting headlights or connectors......

Don't really know, RonNL.  There won't be any heat due to small gauge wires.  I don't drive a lot at night but I will keep an eye on things.


4/28/2014 4:03 PM  #10

Re: Conversion H4 extreme

Nice setup. Thanks for the heads up!


11/29/2015 12:19 PM  #11

Re: Conversion H4 extreme

I completed upgrading the lights on the coupe , what a difference. I went with the hella lamps the upgraded hella bulbs. Anyone who drives at night you really should upgrade to relays, it is worth it.

65 coupe, 351w, c4, power disk brakes, power r&p, vintage air.

Board footera

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