[Rich-Tripower]

This is a 4-speed Tri-power car if it matters. I have a good original underdash harness. The rear harness in the trunk went in without problems or questions, got the back up lights wired in without problems. The underdash harness seems pretty straight forward. I'm now working on the engine compartment harnesses and have a few questions.

1. How does the voltage regulator mount to the firewall? Is it simply screwed to the firewall or does it use rubber encased nuts like my Chevys do?

2. I know there are special wire capture loops on the radiator support. I suspect they mount underneath and the wires run across on the underside of the support cross brace held up by the plastic loops. I have three loops, do I need more? Where else are wire ties used, just on the driver's side inner fender?

3. How does the hose from the washer bottle run, along the radiator support and down the driver's side fender to the wiper motor or along the passenger side fender and then down the firewall? Does the hose run behind the fender support (in the hollow space created by the fender and the inner fender) or in front of it out in the engine compartment?

4. I assume the backup light harness runs through the rectangular hole outboard of where the fuse block comes through the firewall? I have a new harness and the original foam block is useable. I saw a diagram how the wires run down the side of the transmission, but how are they strung from there to the hole in the firewall, what keeps them away from the clutch mechanism and exhaust pipes?

5. The throttle cable, how does it mount to the firewall? I have the cable and the triangular mounting pad has a gasket on it so that makes sense, but there is also a black plastic shield that I have too, does it mount in the engine side or the interior side?

6. My brand new wiring harness has only one wire for a horn yet my car has dual horns. Do I just have to splice in a second wire? (I can scavange one from the old harness.) Can I just splice into the existing horn wire? My old harness was chopped up so I can't see how two wires sprouted from the single green wire coming off the horn relay. Also, how do the wires run from the harness to the horns? Are they routed outboard of the radiator support and routed under the edge at the bottom or do they run inside the radiator space from above? (Does this make sense?) Do they simply dangle from the harness at the top of the radiator support or are they secured somewhat on their way down to the horns? On the passenger side wire, does it run outside the harness wrapping (this is the way my original was) or should that longer horn wire be inside the harness wrapping?

7. Assuming the wiper motor, mine has washers as well, is just wired from the main harness that runs over to the rear of the engine and to the heater blower. I don't have the motor installed yet so it is hard to visualize just yet.

8. How does the antenna lead route through the body? I have a new antenna body and cable, am I going to need to pull the fender off to get it all in place?

9. Are the aftermarket temp sending units any good? I don't have gauges, just a warning light. In the Chevy world we have to use old sending units for proper function, the currently available sending units don't read right (for gauges anyway). I really want to hook in a good oil pressure gauge, at least for when we are breaking in the engine. I assume it is just as simple as installing a fitting in the hole where the oil pressure sending unit is installed in the back of the block. Is there anywhere else I can pick up oil pressure? It would be nice to have both the gauge and the light functioning.

10. Did the GTO come standard with a light in the glovebox? There was never a wire or a switch in this car while I've had it, but maybe it got taken out by a previous owner for some reason.

That's all I can think of for now. Getting down to the nitty gritty! Darn Tempst/LeMans/GTO is sure laid out a lot different than in my 1965 Chevelles. You'd think they'd be pretty similar but that's just not so. Even the rear side window frames are different, probably to accommodate slightly different quarter panel shapes.

Thanks in advance.

[Dick Boneske]

I'll answer a few:

Originally Posted by Rich-Tripower

This is a 4-speed Tri-power car if it matters. I have a good original underdash harness. The rear harness in the trunk went in without problems or questions, got the back up lights wired in without problems. The underdash harness seems pretty straight forward. I'm now working on the engine compartment harnesses and have a few questions.

1. How does the voltage regulator mount to the firewall? Is it simply screwed to the firewall or does it use rubber encased nuts like my Chevys do?

It's screwed directly to the sheet metal with hex head sheet metal screws--about #12.

2. I know there are special wire capture loops on the radiator support. I suspect they mount underneath and the wires run across on the underside of the support cross brace held up by the plastic loops. I have three loops, do I need more? Where else are wire ties used, just on the driver's side inner fender?

Radiator support loops snap in to the holes from the bottom of the support. Three loops should do the trick.

3. How does the hose from the washer bottle run, along the radiator support and down the driver's side fender to the wiper motor or along the passenger side fender and then down the firewall? Does the hose run behind the fender support (in the hollow space created by the fender and the inner fender) or in front of it out in the engine compartment?

Hose runs with the wires through the three loops on the radiator support. Then, to the inside of the driver's side fender and to the pump/motor. At least one metal clip is used to support the hose along the motor side of the fender--in front of the hood hinge.

4. I assume the backup light harness runs through the rectangular hole outboard of where the fuse block comes through the firewall? I have a new harness and the original foam block is useable. I saw a diagram how the wires run down the side of the transmission, but how are they strung from there to the hole in the firewall, what keeps them away from the clutch mechanism and exhaust pipes?

Yes, the backup light harness runs through the rectangular rubber piece to the outside of the fuse block. The wire is routed under the floorboard--held with clips---directly to the transmission switch.

5. The throttle cable, how does it mount to the firewall? I have the cable and the triangular mounting pad has a gasket on it so that makes sense, but there is also a black plastic shield that I have too, does it mount in the engine side or the interior side?

Throttle cable fastens to the firewall with the same type screws that hold the regulator.

6. My brand new wiring harness has only one wire for a horn yet my car has dual horns. Do I just have to splice in a second wire? (I can scavange one from the old harness.) Can I just splice into the existing horn wire? My old harness was chopped up so I can't see how two wires sprouted from the single green wire coming off the horn relay. Also, how do the wires run from the harness to the horns? Are they routed outboard of the radiator support and routed under the edge at the bottom or do they run inside the radiator space from above? (Does this make sense?) Do they simply dangle from the harness at the top of the radiator support or are they secured somewhat on their way down to the horns? On the passenger side wire, does it run outside the harness wrapping (this is the way my original was) or should that longer horn wire be inside the harness wrapping?

There is a separate wire about 60" long that goes from the driver's side horn, over the radiator support through the three loops, and down to the passenger side horn. It has lugs on both ends to attach to the horns.

7. Assuming the wiper motor, mine has washers as well, is just wired from the main harness that runs over to the rear of the engine and to the heater blower. I don't have the motor installed yet so it is hard to visualize just yet.

The connector for the wiper motor is part of the underhood harness that also goes to the blower motor. It will be evident when you mount the motor.

8. How does the antenna lead route through the body? I have a new antenna body and cable, am I going to need to pull the fender off to get it all in place?

The antenna wire enters the interior through a hole and grommet on the passenger side just below the rubber strip that seals the rear of the hood. No, you do not have to pull the fender off to route the wire.

9. Are the aftermarket temp sending units any good? I don't have gauges, just a warning light. In the Chevy world we have to use old sending units for proper function, the currently available sending units don't read right (for gauges anyway). I really want to hook in a good oil pressure gauge, at least for when we are breaking in the engine. I assume it is just as simple as installing a fitting in the hole where the oil pressure sending unit is installed in the back of the block. Is there anywhere else I can pick up oil pressure? It would be nice to have both the gauge and the light functioning.

Check Rockauto.com. The sending unit for temp and lights works just fine. For the oil pressure gage, a special sending unit is needed which is screwed into the oil filter bracket (1/8" pipe threads). You could use a tee there and mount both idiot light and gage senders. I don't know off hand where else to tap into oil pressure lines.

10. Did the GTO come standard with a light in the glovebox? There was never a wire or a switch in this car while I've had it, but maybe it got taken out by a previous owner for some reason.

Glove box light is optional. The light comes with a harness that plugs into the underdash harness.

That's all I can think of for now. Getting down to the nitty gritty! Darn Tempst/LeMans/GTO is sure laid out a lot different than in my 1965 Chevelles. You'd think they'd be pretty similar but that's just not so. Even the rear side window frames are different, probably to accommodate slightly different quarter panel shapes.

Thanks in advance.

[Rich-Tripower]

Thanks! Especially on the horn wiring, I was beginning to wonder if it worked like that somehow. I might have to make a harness for the passenger horn.

Concerning the throttle cable, how is the black plastic shield involved? I can post a picture of it if it would help.

[Dick Boneske]

The black plastic piece goes between the firewall and the triangular cable holder. It mounts on the engine side of the firewall. As you can see from my picture in the earlier post, I used a little dum-dum also, to seal it better with the firewall.

[bill ryder]

Beautiful tri fold boot, Dick!! I am very jealous! "Bill"!

[Tom Vaught]

In Dick B's second picture you see the pivot bracket for the solid rod gas pedal to carb.

Anyone have the rest of the pieces for that deal laying around?

Tom V.

[Rich-Tripower]

Sorry, didn't even notice the photos before. What is the second wire coming through the foam block where the back up light switch wires go through?

[Rich-Tripower]

Got a lot done tonight. Throttle cable in, VR mounted, lots of wiring under the hood connected. I have a few new questions.

11. Should the vacuum advance can point toward the passenger or driver's side? I currently have it point to the driver's side with the fitting on the center carb pointing the same direction but maybe it should be on the other side?

12. Just double checking here. The positive battery cable connects to the stud on the horn relay on the inner fender. Then another cable runs from the horn relay to the starter. A large red loom wire also connects to the stud. The negative battery cable connects to a stud on the cylinder head between the first two spark plugs. I also have a stud on the thermostat housing but I think that had something to do with the vacuum controls for the tripower (which we've removed in favor of a progressive linkage).

13. The horn relay mounts with the horn wires on top and the battery cables on the bottom, correct?

Thanks again.

[Dick Boneske]

Originally Posted by Rich-Tripower

Got a lot done tonight. Throttle cable in, VR mounted, lots of wiring under the hood connected. I have a few new questions.

11. Should the vacuum advance can point toward the passenger or driver's side? I currently have it point to the driver's side with the fitting on the center carb pointing the same direction but maybe it should be on the other side?

Vacuum advance should point toward the windshield wiper motor.

12. Just double checking here. The positive battery cable connects to the stud on the horn relay on the inner fender. Then another cable runs from the horn relay to the starter. A large red loom wire also connects to the stud. The negative battery cable connects to a stud on the cylinder head between the first two spark plugs. I also have a stud on the thermostat housing but I think that had something to do with the vacuum controls for the tripower (which we've removed in favor of a progressive linkage).

The red positive cable goes on the horn relay large (3/8") stud. On top of that, a large black wire runs between the exh. manifold and starter (3/8") stud. Negative battery cable goes directly to the head bolt stud between cyl. #1 and #3. The stud on the thermostat housing is used for the rear alternator strap--if you use one. Otherwise, there is just a bolt in that hole and the alternator strap is held by one of the water pump cover bolts.

13. The horn relay mounts with the horn wires on top and the battery cables on the bottom, correct?

Yes.

Thanks again.

Here's some more info.

[bill ryder]

Washer hose goes behind the dr hood hinge. A clip in front and behind the hinge secure it to the fender. "Bill"!

[Rich-Tripower]

All good stuff. On hold to place my (hopefully) last parts order.

[Rich-Tripower]

Follow up question on the dual horns wiring harness. I got a new one from M&H and it is ridiculously long. It just goes from the driver's side horn, up to the radiator support, across and down to the passenger side horn, right? If I take that route I end up with 3-4 feet of extra wire. For now I ran the excess back up to the radiator support and tucked it into the wiring clips. I'm thinking M&H made it wrong (too long) or it takes a different route I am not aware of.

I just spoke with M&H and they work from the original GM blueprints and it was originally listed as being 102 inches long and was later updated on Jan. 1964 to be 106 inches long. That explains why it came to me so long, but that just can't be right. They said they would be happy to alter it to the correct length but I want to confirm with the knowledgebase here that what I have is way too long.

[Rich-Tripower]

Originally Posted by Rich-Tripower

Follow up question on the dual horns wiring harness. I got a new one from M&H and it is ridiculously long. It just goes from the driver's side horn, up to the radiator support, across and down to the passenger side horn, right? If I take that route I end up with 3-4 feet of extra wire. For now I ran the excess back up to the radiator support and tucked it into the wiring clips. I'm thinking M&H made it wrong (too long) or it takes a different route I am not aware of.

I just spoke with M&H and they work from the original GM blueprints and it was originally listed as being 102 inches long and was later updated on Jan. 1964 to be 106 inches long. That explains why it came to me so long, but that just can't be right. They said they would be happy to alter it to the correct length but I want to confirm with the knowledgebase here that what I have is way too long.

bump

[Pecosbill]

On the wire running through the firewall grommet to the backup light switch, there is suppose to be a small bracket mounted on the bottom of the firewall that the wire passes through. That holds the wire away from the clutch mechanism as well as the exhaust.

[JAKE 64]

For 1964

Just a couple of comments to hopefully clarify:

?2 There are five plastic black plastic straps used. Our host refers to these as "compartment straps". I have noted two vendors used, one of which is currently reproduced and bares the embossed P-4007. These straps run along the rearwood side of the upper core support channel. For references, No. 1 strap is located at the point where the core support fastens to the left (driver) side fender, and the No. 5 strap is at the point where the core support fastens to the right fender. For the LeMans/GTO, the straps are mounted as follows. The No. 1 and 5 straps are pushed into the rear vertical face of the upper core support channel from the engine side. Looking down at these two straps, the entire strap would be visible. Strap Nos. 2, 3, and 4 are pushed into the vertical face of the upper core support from the front to rear, so that the bulk of the strap is hidden under the upper core support. Looking down at these three straps, only the attaching knobs (?) would be visible.

?3 The hose from the washer jug is routed through straps 4, 3, 2, and 1. The hose is then held in place by a metal clip mounted on the fender flange, 3.5" (10.5" from core support) to the rear of the mounted battery. The hose then runs hidden under the fender, until it exits, and is held in place by a second metal clip mounted to the fender flange between the left hood hinge and fire wall. (photos of this arrangement and clips are in this forum, I believe included with Bill Ryders Comments and Criticism thread.)

?4 A detailed discussion of the back-up light routing was discussed a couple of months back, and should help.

?5 You must have a very late model car, as I have yet to see the black plastic (see photos below) Throttle Control Cable Dash Stop (Stop - Part No. 9776989) used in a 1964 application. The use of the Stop can be discerned by the diameter of the hole in your firewall. The earlier applications did not use this Stop, and as such, a 1/2" diameter flanged hole was provided in the firewall, with a black triangular shaped gasket used. The 1/2" diameter firewall hole permitted the passage of the 3/8" high clevis through the firewall. When the Stop was used, the firewall hole was increased to at least 1 1/16" diameter to accept the Stop. I am not familiar with the use of the Throttle Control Dash Stop Retainer (Retainer - Part No. 9776988). I don't believe the Retainer was provided, as the triangular shaped cable assembly, Stop, and gaskets were secured from the engine side by three cadmium plated hex headed screws. I don't understand the need nor have ever seen a retainer used when the Stop (prevalent in 1965) was used.

?6 You asked for the routing of the horn-to-horn wire, but for reference sake, I'll start at the main harness. The first green horn wire leaves the main harness where the left (driver) side fender bolts to the core support just ahead of the battery. This wire bypasses Compartment Strap No. 1 and is routed directly through the 1" diameter flared hole in the core support (along with the purple and blue wires to the turn signal light) ending at the left side (low) horn. The 2nd green wire (same shade of green) plugs into the left side horn and is routed back up through the core support alongside the first green wire and turn signal wires. This 2nd wire is routed through Compartment Strap Nos. 1, 2, 3, 4, and 5. It is then routed through the 1" diameter flared hole in the right side of the core support (along with the right side turn signal wires) to the right side, (high) horn. I had an original 2nd horn wire handy, and measured this wire. From black connector to connector, it measured 106 in. long. If I had pulled this wire taut, I probably would have had 108 in. You'll need all of it. (See photos below)

[Rich-Tripower]

Car was built in July if I remember right.