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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 75
Location: Tulsa, OK
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 Posted: Sat Nov 08, 2025 7:25 pm Post subject: Voltage regulator wiring |
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At some point before I bought my ‘63, someone moved the voltage regulator from under the seat and mounted it on the generator. I need to redo the wire connecting the voltage regulator to the starter/battery and can’t find the wire size printed on the wire.
Is it 10 or 8 ga? |
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slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Sat Nov 08, 2025 8:16 pm Post subject: Re: Voltage regulator wiring |
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If it's original wiring, it's metric, and won't be identified by AWG sizes.
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes?  |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
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EVfun 
Samba Member
Joined: April 01, 2012
Posts: 6407
Location: Seattle
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| Posted: Sat Nov 08, 2025 8:32 pm Post subject: Re: Voltage regulator wiring |
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A '63 is supposed to have the voltage regulator mounted on the generator, not under the back seat like later 12 volt Bugs.
If you want to duplicate the generator wiring setup used on 12 volt Bugs I would recommend copying the '67 wiring diagram. 6.0mm is best substituted with 8 gauge wire and 1.0mm is best substituted with 16 gauge wire (for both the wire will be slightly larger than original for a 12 volt generator car). It would likely be easier to convert the car to a 12 volt alternator with built in regulator.
_________________
| Wildthings wrote: |
| As a general rule, cheap parts are the most expensive parts you can buy. |
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JBradford84
Samba Member
Joined: April 15, 2025
Posts: 75
Location: Tulsa, OK
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| Posted: Sat Nov 08, 2025 8:43 pm Post subject: Re: Voltage regulator wiring |
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Thanks for the info. I wasn’t aware that 63 had them installed on the generator. I was assuming this one was moved when the car was converted to 12v.
It’s nowhere near a restoration, so keeping is stock-ish isn’t an issue. I just didn’t want to burn up the wiring.
Thanks again. |
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runamoc
Samba Member
Joined: June 19, 2006
Posts: 6497
Location: 37.5N 77.1W
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| Posted: Sun Nov 09, 2025 9:09 am Post subject: Re: Voltage regulator wiring |
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wires? they are just wires..
_________________
Daily driver: '69 Baja owned 45 yrs - Plan B: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs- '80 Rabbit Diesel
VW Wiring = It's just wires |
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ashman40
Samba Member
Joined: February 16, 2007
Posts: 16802
Location: North Florida, USA
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| Posted: Sun Nov 09, 2025 10:15 am Post subject: Re: Voltage regulator wiring |
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| EVfun wrote: |
| A '63 is supposed to have the voltage regulator mounted on the generator, not under the back seat like later 12 volt Bugs. |
Here's a page from the '63 Beetle Owners Manual showing the generator mounted VR:
Here's a real pic of a 40HP engine from the Engine Guide thread:
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road  }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Sun Nov 09, 2025 11:48 am Post subject: Re: Voltage regulator wiring |
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| runamoc wrote: |
wires? they are just wires..
|
I like that. It's a very handy chart. 
I used to remind my people that the wire doesn't know or care what color it is
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes? |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
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runamoc
Samba Member
Joined: June 19, 2006
Posts: 6497
Location: 37.5N 77.1W
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| Posted: Sun Nov 09, 2025 12:35 pm Post subject: Re: Voltage regulator wiring |
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| slayer61 wrote: |
| runamoc wrote: |
wires? they are just wires..
|
I like that. It's a very handy chart.
I used to remind my people that the wire doesn't know or care what color it is |
when I made my own wiring harness I used LEDS lights and a HSR, so I was able to use smaller than stock wire gauges. With this extra 'space' I ran 2 #10guage wires to the front. One connected to the lights switch. The other to #30 wire on the fuse panel.
it shows that 2 #12gauge wires can carry more current than one #8gauage, and 2 #10gauage wires can carry more current than one #6gauage wire. For some reason owners will spend more money on the bigger wire. 
I'm in favor off point A to point B wire connections and hate 'in the middle' connections
_________________
Daily driver: '69 Baja owned 45 yrs - Plan B: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs- '80 Rabbit Diesel
VW Wiring = It's just wires |
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EVfun
Samba Member
Joined: April 01, 2012
Posts: 6407
Location: Seattle
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| Posted: Sun Nov 09, 2025 1:39 pm Post subject: Re: Voltage regulator wiring |
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| runamoc wrote: |
when I made my own wiring harness I used LEDS lights and a HSR, so I was able to use smaller than stock wire gauges. With this extra 'space' I ran 2 #10guage wires to the front. One connected to the lights switch. The other to #30 wire on the fuse panel.
it shows that 2 #12gauge wires can carry more current than one #8gauage, and 2 #10gauage wires can carry more current than one #6gauage wire. For some reason owners will spend more money on the bigger wire.
I'm in favor off point A to point B wire connections and hate 'in the middle' connections
|
While two 12 gauge wires can carry more current than one 8 gauge wire the two 12 gauge wires will have slightly more voltage drop at the same total current. I wired my buggy in a similar fashion, with the fuse block by the battery and two 12 gauge wires running to the front, a yellow one going to the light switch and a red one going to the ignition switch.
I have my own little cheat sheet to determine wire size for automotive work. I notice that manufacturers often use even smaller wire sizes than this:
| Code: |
AWG mm^2 mOhm/ft amps dia”
2 33.6 .156 100 .2576
4 21.2 .248 82 .2043
6 13.3 .395 65 .1620
8 8.37 .628 50 .1285
10 5.26 .999 36 .1019
12 3.31 1.59 25 .0808
14 2.08 2.53 16 .0641
16 1.31 4.02 10 .0508
18 .823 6.39 6 .0403
20 .518 10.2 3.5 .0320 |
_________________
| Wildthings wrote: |
| As a general rule, cheap parts are the most expensive parts you can buy. |
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slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Sun Nov 09, 2025 2:43 pm Post subject: Re: Voltage regulator wiring |
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| runamoc wrote: |
| slayer61 wrote: |
| runamoc wrote: |
wires? they are just wires..
|
I like that. It's a very handy chart.
I used to remind my people that the wire doesn't know or care what color it is |
when I made my own wiring harness I used LEDS lights and a HSR, so I was able to use smaller than stock wire gauges. With this extra 'space' I ran 2 #10guage wires to the front. One connected to the lights switch. The other to #30 wire on the fuse panel.
it shows that 2 #12gauge wires can carry more current than one #8gauage, and 2 #10gauage wires can carry more current than one #6gauage wire. For some reason owners will spend more money on the bigger wire.
I'm in favor off point A to point B wire connections and hate 'in the middle' connections
|
My line of work had minimum standards that "shall be" adhered to, and one of those minimums was the minimum size of parallel conductors. #12 did NOT meet the minimum. My line of work, did not include cars, however.
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes? |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
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slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Sun Nov 09, 2025 2:46 pm Post subject: Re: Voltage regulator wiring |
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| EVfun wrote: |
| runamoc wrote: |
when I made my own wiring harness I used LEDS lights and a HSR, so I was able to use smaller than stock wire gauges. With this extra 'space' I ran 2 #10guage wires to the front. One connected to the lights switch. The other to #30 wire on the fuse panel.
it shows that 2 #12gauge wires can carry more current than one #8gauage, and 2 #10gauage wires can carry more current than one #6gauage wire. For some reason owners will spend more money on the bigger wire.
I'm in favor off point A to point B wire connections and hate 'in the middle' connections
|
While two 12 gauge wires can carry more current than one 8 gauge wire the two 12 gauge wires will have slightly more voltage drop at the same total current. I wired my buggy in a similar fashion, with the fuse block by the battery and two 12 gauge wires running to the front, a yellow one going to the light switch and a red one going to the ignition switch.
I have my own little cheat sheet to determine wire size for automotive work. I notice that manufacturers often use even smaller wire sizes than this:
| Code: |
AWG mm^2 mOhm/ft amps dia”
2 33.6 .156 100 .2576
4 21.2 .248 82 .2043
6 13.3 .395 65 .1620
8 8.37 .628 50 .1285
10 5.26 .999 36 .1019
12 3.31 1.59 25 .0808
14 2.08 2.53 16 .0641
16 1.31 4.02 10 .0508
18 .823 6.39 6 .0403
20 .518 10.2 3.5 .0320 |
|
Yes. Manufacturers are held to a different standard than common folk. They normally have to satisfy the UL however
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes? |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
|
| Back to top |
|
|
EVfun
Samba Member
Joined: April 01, 2012
Posts: 6407
Location: Seattle
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| Posted: Sun Nov 09, 2025 3:48 pm Post subject: Re: Voltage regulator wiring |
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| slayer61 wrote: |
| Yes. Manufacturers are held to a different standard than common folk. They normally have to satisfy the UL however |
I don’t think auto makers have to comply with UL listing. I’ve seen a wire between 16 gauge and 18 gauge (most likely 1.0mm) being used to ground both headlights through a stalk mounted light switch (Geo Metro). I had to fix the mess that resulted at about 100k miles. My Tacoma uses the same basic design and is known to have headlight issues (less often, so there must be a little more copper). Just the idea that all the lights are either powered or grounded through a tight bundle of wires running through steering column — they don’t seem to have heard about derating either.
Most of the time I’m more concerned about late fusing issues, over wire size issues, in homemade wiring solutions. Oh, and either color coding or wire labeling would really help when something doesn’t work. (Autos are big on color coding, UL is big on labeling.)
_________________
| Wildthings wrote: |
| As a general rule, cheap parts are the most expensive parts you can buy. |
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runamoc
Samba Member
Joined: June 19, 2006
Posts: 6497
Location: 37.5N 77.1W
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| Posted: Sun Nov 09, 2025 6:47 pm Post subject: Re: Voltage regulator wiring |
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[quote="EVfun"]
| runamoc wrote: |
While two 12 gauge wires can carry more current than one 8 gauge wire the two 12 gauge wires will have slightly more voltage drop at the same total current.
| Code: |
AWG mm^2 mOhm/ft amps dia”
2 33.6 .156 100 .2576
4 21.2 .248 82 .2043
6 13.3 .395 65 .1620
8 8.37 .628 50 .1285
10 5.26 .999 36 .1019
12 3.31 1.59 25 .0808
14 2.08 2.53 16 .0641
16 1.31 4.02 10 .0508
18 .823 6.39 6 .0403
20 .518 10.2 3.5 .0320 |
|
went to this web-site and ran the numbers for 2 parallel #12 gauge copper conductors vs. single #8gauge copper conductor for voltage drop difference for 10 feet using 12volts. There is a .04 volts drop difference for the 2 #12gauge wires vs one #8guage wire. Yeah, slightly more voltage drop on the 2 wires. Not sure if my VOM is accurate enough to read that difference. 
https://www.calculator.net/voltage-drop-calculator...;ctype=nec
_________________
Daily driver: '69 Baja owned 45 yrs - Plan B: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs- '80 Rabbit Diesel
VW Wiring = It's just wires |
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slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Sun Nov 09, 2025 7:30 pm Post subject: Re: Voltage regulator wiring |
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^^^ you do all this without a meter that reads millivolts?? ^^^
Much respect
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes? |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
|
| Back to top |
|
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runamoc
Samba Member
Joined: June 19, 2006
Posts: 6497
Location: 37.5N 77.1W
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| Posted: Mon Nov 10, 2025 7:34 am Post subject: Re: Voltage regulator wiring |
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| Quote: |
| meter that reads millivolts? |
never really had the need to measure millivolts on a VW electrical system.
_________________
Daily driver: '69 Baja owned 45 yrs - Plan B: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs- '80 Rabbit Diesel
VW Wiring = It's just wires |
|
| Back to top |
|
|
slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Mon Nov 10, 2025 8:44 am Post subject: Re: Voltage regulator wiring |
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| runamoc wrote: |
| Quote: |
| meter that reads millivolts? |
never really had the need to measure millivolts on a VW electrical system. |
I see. I used them regularly to check voltage drop across a shunt on an amp meter. Just different worlds.
Be well brother
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes? |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
|
| Back to top |
|
|
runamoc
Samba Member
Joined: June 19, 2006
Posts: 6497
Location: 37.5N 77.1W
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| Posted: Mon Nov 10, 2025 8:55 am Post subject: Re: Voltage regulator wiring |
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| Quote: |
| voltage drop across a shunt on an amp meter |
doesn't the amp meter do that for you? 50mv=FullScale
_________________
Daily driver: '69 Baja owned 45 yrs - Plan B: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs- '80 Rabbit Diesel
VW Wiring = It's just wires |
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| Back to top |
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slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Mon Nov 10, 2025 11:01 am Post subject: Re: Voltage regulator wiring |
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It does, if it's accurate and working. It was a double check on critical systems
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes? |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
|
| Back to top |
|
|
runamoc
Samba Member
Joined: June 19, 2006
Posts: 6497
Location: 37.5N 77.1W
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| Posted: Mon Nov 10, 2025 12:48 pm Post subject: Re: Voltage regulator wiring |
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How? With another meter?
_________________
Daily driver: '69 Baja owned 45 yrs - Plan B: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs- '80 Rabbit Diesel
VW Wiring = It's just wires |
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| Back to top |
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slayer61
Samba Member
Joined: June 01, 2021
Posts: 1398
Location: TX
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| Posted: Mon Nov 10, 2025 3:07 pm Post subject: Re: Voltage regulator wiring |
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| runamoc wrote: |
How? With another meter? |
Sure. The analog device lived out in the field exposed to the elements. The digital volt meter was kept stored in doors and was calibrated annually. The millivolt is also the output of a thermocouple, could be used to test voltage drop across a relay or motor starter on a DC circuit.
The power plants i worked in are quite regulated and overseen by NERC. The North American Electric Reliability Council.
Emphasis on RELIABILITY
_________________
| Cusser wrote: |
... Most folks are idiots when it deals with electrical !!! |
| 67rustavenger wrote: |
3/4 race cam? What's missing, one of the lobes? |
Paul
'68 Manx clone... Sears??
RLR/Strange brakes
2276 built on AS21 case
W-125 w/ GB 1.25:1 rockers
Mahle forged pistons
CB 4340 crank
CB H beam rods
deep sump
45 DCOE
Garrett turbo
Tim's stage II turbo heads
MSD Box and distributor
Car Craft turbo header |
|
| Back to top |
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