Distributor/ignition and wiring

[Rich77]

Hey guys,

My truck is a 1977 C10 sbc400/th350

I have a Summit Racing "ready to run" billet distributor (Sum850205) and a MSD Ignition 8207 Blaster SS Coil.

This is the distributor: https://www.summitracing.com/parts/sum-850205

This is the coil: https://www.summitracing.com/parts/msd-8207

Do I need an ignition box?

I don't know how to wire any of this.

 

[Bextreme04]

Hey guys,

My truck is a 1977 C10 sbc400/th350

I have a Summit Racing "ready to run" billet distributor (Sum850205) and a MSD Ignition 8207 Blaster SS Coil.

This is the distributor: https://www.summitracing.com/parts/sum-850205

This is the coil: https://www.summitracing.com/parts/msd-8207

Do I need an ignition box?

I don't know how to wire any of this.

No, you don't need an ignition box. Its says so right in the description of the part that you posted. It should have instructions for wiring it right there in the box.. it's not hard, just power and ground that should already be there for the factory HEI.

 

[Rich77]

Thanks! Sometimes people tell you other things that make you second guess.

 

[Rich77]

So if I’m wiring this correctly (the engine harness was missing when I got the truck), the pink wire would go to the choke, blue wire would go to the oil sensor, green wire to water temp sensor…

 

[Bextreme04]

If you have an aftermarket harness that is supposed to mimic the factory one, then yes. The coolant temp sensor should be in the drivers side head though. Electric choke should be running through an oil pressure switch above the oil filter so that it doesn't start pulling the choke off until the engine is actually running.

 

[Rich77]

The coolant temp sensor should be in the drivers side head though.

The problem is that the port in my heads is 3/8”. I couldn’t find a sensor that would work that’s 3/8”. They’re all 1/2”.

Electric choke should be running through an oil pressure switch above the oil filter so that it doesn't start pulling the choke off until the engine is actually running.

So I should run a jumper from the oil pressure switch to the choke?

 

[Bextreme04]

The problem is that the port in my heads is 3/8”. I couldn’t find a sensor that would work that’s 3/8”. They’re all 1/2”.

So I should run a jumper from the oil pressure switch to the choke?

I would maybe run the power straight to the choke. Then remove the jumper from the ground plug to the carb body and replace it with a wire running down to the oil pressure switch. Then from the other side of the oil pressure switch to a good ground point.

This will be a switch that is NO and goes closed when it sees pressure above ~5psi or so.

You can get adapters to go from 3/8" to 1/2", but most new coolant sensors come in 3/8" and you have to use an adapter to go the other way.

 

[Rich77]

I would maybe run the power straight to the choke. Then remove the jumper from the ground plug to the carb body and replace it with a wire running down to the oil pressure switch. Then from the other side of the oil pressure switch to a good ground point.

What if I have a mechanical gauge?

You can get adapters to go from 3/8" to 1/2", but most new coolant sensors come in 3/8" and you have to use an adapter to go the other way.

I did try a reducer/adapter. But then the sensor was out of the head an inch or more.

 

[Bextreme04]

What if I have a mechanical gauge?

The Gauge should be getting the feed from the port on the back of the block next to the distributor. The choke switch is an electrical switch that threads into the block above the oil filter on the side of the block. You might need to buy a switch if you want to have that feature, otherwise just leave it as-is and know that you shouldn't sit there with the ignition on and the truck off before trying to start it.

I did try a reducer/adapter. But then the sensor was out of the head an inch or more.

I just realized you have the early nailhead style sender. Unfortunately the options are limited with those. You can convert to the newer style that does come in the 3/8" thread, but then you would need to change the resistor on the back of your gauge to match.

You don't necessarily need to move it from the intake, but you will read a lower temp there than you would at the head, so just be aware.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=32806.0

 

[Rich77]

The Gauge should be getting the feed from the port on the back of the block next to the distributor. The choke switch is an electrical switch that threads into the block above the oil filter on the side of the block. You might need to buy a switch if you want to have that feature, otherwise just leave it as-is and know that you shouldn't sit there with the ignition on and the truck off before trying to start it.

ELECTRIC CHOKE SWITCH OIL PRESSURE SWITCH CHEVROLET & CHEVROLET GMC TRUCK & VAN | eBay

1986 V6-173ci 2.8L F/I Vin R. 1987 V8-379ci 6.2L Diesel Vin J. 1986 V6-262ci 4.3L F/I Vin Z. 1982 V8-305ci 5.0L 4 BBL Vin H. 1985 L6-292ci 4.8L 1 BBL Vin T. 1985 V8-350ci 5.7L 4 BBL Vin M. 1986 V8-350ci 5.7L 4 BBL Vin M.

www.ebay.com

So I would use a switch like this^^

Run my oil sensor wire to one connector and then run a wire from the other connector to the choke?

 

[Bextreme04]

ELECTRIC CHOKE SWITCH OIL PRESSURE SWITCH CHEVROLET & CHEVROLET GMC TRUCK & VAN | eBay

1986 V6-173ci 2.8L F/I Vin R. 1987 V8-379ci 6.2L Diesel Vin J. 1986 V6-262ci 4.3L F/I Vin Z. 1982 V8-305ci 5.0L 4 BBL Vin H. 1985 L6-292ci 4.8L 1 BBL Vin T. 1985 V8-350ci 5.7L 4 BBL Vin M. 1986 V8-350ci 5.7L 4 BBL Vin M.

www.ebay.com

So I would use a switch like this^^

Run my oil sensor wire to one connector and then run a wire from the other connector to the choke?

Oil sensor wire goes to an oil pressure sensor. Full stop, the end.

Then, completely separate from the oil pressure sensor:

Choke power wire would go to one terminal of that switch, then the other terminal goes to the choke.
OR
Choke power wire goes to the choke, then choke ground goes from the choke to one termianl on that switch and the other terminal on that switch goes to a good ground location.