350 swap questions

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Jerryred94silvy

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Do any of y’all know how to make 1994 gauges work with these sending units?
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I imagine it’s just connecting a ground somewhere.
 

Rich-stepside

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Do any of y’all know how to make 1994 gauges work with these sending units?
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I imagine it’s just connecting a ground somewhere.

Honestly I'd probably just switch them to the correct senders
For a 94. They are cheap ,easy to change ,and just plug in to
The factory harness
 

Jerryred94silvy

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So I put the 4.3 coolant sensor in the driver side head of the 350 and it seems to work, the needle starts to move upwards as the truck warms up. However, the gauge tells me that the engine never gets above 130 degrees or so (whatever two pegs above 100 is). Even after driving it for 15 minutes and letting it idle at the destination for another 5-10 minutes. I never felt excessive heat from the engine bay and the truck never behaved any differently. Is this normal? Or should I make sure the gauge and respective wiring are working properly?

Edit~My family’s GMT800 trucks usually sit around the 210 mark and that’s what I’m used to seeing.
 

94bigoleblue

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What transmission are you running. Did u have to hook up any vaccuum lines? I have a 4l80e and trans doesn't seem to shift as firm as before.
 

Supercharged111

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So I put the 4.3 coolant sensor in the driver side head of the 350 and it seems to work, the needle starts to move upwards as the truck warms up. However, the gauge tells me that the engine never gets above 130 degrees or so (whatever two pegs above 100 is). Even after driving it for 15 minutes and letting it idle at the destination for another 5-10 minutes. I never felt excessive heat from the engine bay and the truck never behaved any differently. Is this normal? Or should I make sure the gauge and respective wiring are working properly?

Edit~My family’s GMT800 trucks usually sit around the 210 mark and that’s what I’m used to seeing.

My 88 C1500 was like that when I bought it. Turned out to be a junk thermostat.
 

Schurkey

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The oem V6 a/c and tensioner bracket don’t bolt to this V8. The power steering/alternator bracket fits minty though.
I should probably mention (I thought I had, whoops) that I have aftermarket aluminum heads and that’s probably why it doesn’t fit.
You have aluminum heads that DON'T have accessory bolt holes? I didn't know they made such a thing. What brand of heads? What part number?

No accessory bolt holes = you're screwed.

In-focus, nicely-cropped-and-sized photos of the heads, and the brackets you're trying to use?


the gauge tells me that the engine never gets above 130 degrees or so (whatever two pegs above 100 is). Even after driving it for 15 minutes and letting it idle at the destination for another 5-10 minutes. I never felt excessive heat from the engine bay and the truck never behaved any differently. Is this normal? Or should I make sure the gauge and respective wiring are working properly?

Edit~My family’s GMT800 trucks usually sit around the 210 mark and that’s what I’m used to seeing.
So drop a thermometer into the radiator after removing the rad cap, and find out what the temperature is. I'd expect 170-ish at the rad cap, since you'd be on the cool side of the radiator.

https://www.amazon.com/Robinair-10597-Dial-Thermometer-220°F/dp/B000O3M5CE/ref=sr_1_3?keywords=Robinair+thermometer&qid=1582511743&sr=8-3

Some folks use an infrared thermometer directed on the thermostat housing. Others screw an aftermarket temp gauge sending unit into a water port on the engine somewhere. Whatever you do, the concept is to verify the existing sending unit and gauge with a secondary measurement system.
 

Jerryred94silvy

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What transmission are you running. Did u have to hook up any vaccuum lines? I have a 4l80e and trans doesn't seem to shift as firm as before.
It’s a 4l60 using a US Shift TPS sensor running through the stock computer with the purple/white wire run to the tach position on the distributor cap. The tranny has been beefed up, so it shouldn’t ever come close to popping on me (hopefully...)
 

Jerryred94silvy

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My 88 C1500 was like that when I bought it. Turned out to be a junk thermostat.
I checked the thermostat and it was working just fine.


You have aluminum heads that DON'T have accessory bolt holes? I didn't know they made such a thing. What brand of heads? What part number?

No accessory bolt holes = you're screwed.

In-focus, nicely-cropped-and-sized photos of the heads, and the brackets you're trying to use?



So drop a thermometer into the radiator after removing the rad cap, and find out what the temperature is. I'd expect 170-ish at the rad cap, since you'd be on the cool side of the radiator.

https://www.amazon.com/Robinair-10597-Dial-Thermometer-220°F/dp/B000O3M5CE/ref=sr_1_3?keywords=Robinair+thermometer&qid=1582511743&sr=8-3

Some folks use an infrared thermometer directed on the thermostat housing. Others screw an aftermarket temp gauge sending unit into a water port on the engine somewhere. Whatever you do, the concept is to verify the existing sending unit and gauge with a secondary measurement system.
I’ll try all of that stuff when I get the chance and also get those pictures up as well.

There ARE accessory bolt holes, just not in the same locations as the stock cast iron heads. And I looked up and down those heads and couldn’t find any identification on them at all.
 

Jerryred94silvy

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I can’t get a good shot of the heads But here’s the build sheet at least
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Schurkey

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There's no brand-name or model number. I have a hard time believing that a manufacturer would sell a head that didn't have the factory positions for the accessory holes.

Possible exception: Dumbass Communist Chinese screwed-up the position of the holes; it's a manufacturing defect.

Thus the desire for photos to see what's going on.

HOW FAR out of alignment are the existing holes in the head vs. the holes in the accessory bracket?

For the record,
a "racing" valve job isn't going to last long on the street. The seats are too narrow, not enough heat transfer from valve to seat to heat to coolant.

.001 clearance on the exhaust valve-to-guide is asking for trouble.
 
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