Temp sender wire route?

[Rust-O-Matic]

I've rewired my whole '66 with factory style harnesses, and can't figure out how the green wire from the engine harness is supposed to be routed to the coolant temp sender in the driver side head of my 305. The wire comes from the harness that passes thru the firewall near the heater box.

Anybody got a pic? Is that wire supposed to run along the top of the head/edge of intake and down around the front? Does it run behind the head and along the underside of the valve cover just above the header/exhaust? Mine doesn't seem long enough to reach in either of those locations, and seems like the header flange would burn it. Does it just drape over the valve cover and down over the header/ex manifold?

[DPowers]

I believe the original location would have been on the passenger side into the sender in the water neck and would have been routed between the intake and the head.

[jtrichard]

RUST you need to clarify that your 305 is a V8 whenever you post an engine type question when you said that the sender was in the drivers side i went looking through you posts to see if you had a V6 or V8 (found its a 305 V8) when "305" is said around here most will think V6 (AS i believe DPOWERS has above) ..... As for the wire it should be in the harness that goes to the coil then branches off to the sender which was in the drivers side of the intake on the 66 as you can see in post 55 and 59 here http://67-72chevytrucks.com/vboard/s...=324870&page=3 you will have to extend the wire over the rocker cover or around the front ... also the wires to your alternator may also be in the same harness i believe

[Rust-O-Matic]

Sorry for the confusion, fellas. I should have clarified it's a '66 Chevy not GMC, and it has a late 70's Chevy 305 V8 (boo, hiss, lol). It's not a speed machine, but it runs just fine.

I think that link verifies my assumption that stock V8's in '66 had a different temp sender location compared to my current setup. The wire does come from the same harness as the starter and ignition wires (alternator comes from the driver side), and looks like it would go right to a temp sender near the water neck.

I wanted to be sure I was looking at this correctly before I started cutting wires on a brand new, fairly expensive harness to extend it. Should I use some sort of tubing or something as conduit where the extended wire will go by the header on that side? It doesn't look like there's anything there to secure the wire to, to keep it from getting melted.

[jtrichard]

IF the wire is on the PASS side then move the sender to the right side head (will it reach then?)

[Rust-O-Matic]

That's a good question! I hadn't thought about that. I presume the sender could be switched to the passenger side if both heads are identical and the header on that side will clear it. I'll look into that this evening. Just picked up a bag of dash knobs and stuff from Classic Parts on my lunch break, so I will be messing with it again this evening anyway. Thanks for the idea.

[jdl71]

SBC heads are identical and reverse-able. (There is no left and right). So if you have a fitting on one side you should have plug or fitting on the other also.

[Rust-O-Matic]

It definitely looks like the sender could be swapped to the back of the passenger head. After looking everything over though, it looks like it would be pretty difficult to accomplish that without destroying fresh paint on nearby parts. I presume that plug is stuck pretty good after all these years, and would require a fair bit of wrestling to remove. I wish I woulda swapped the sender over before I mounted a new pair of headers.

I think I'll just lengthen the sender wire afterall, and maybe bend a piece of brake line tubing or something to use as conduit, keeping the wire away from the header.

[jdl71]

You could also try moving it to the intake or a t-stat housing with a port in it. I know some people will say it's more accurate in the head and it very well may be, but if you're using the 6cyl harness that's about exactly where your harness will reach to.