Moi,

Never seen 5,7 in person. And remember very little of 6,2 I used to have years ago. But happen to have a manual that might possibly help you.
Looks like there have been at least three types of VRVs (see picture 1526).
The wires that come from vac switch - signal used for TCC.

Toivottavasti tämä auttaa.

 

Yes, those pics from manual sort this out well. One of those VRV's (on pic 1526) do not have electric wire, so suppose it is not used with transmission with TCC (used with THM400 ?). Mine pick up has that (THM350C, RPO: MV4) so wire attachment is needed. Also it do not have any of EGR stuff which needs also VRV system.
Moro, kiitos hyvin selvitti asiaa.

 

Wow, been a minute since I saw one of those. You have a very unusual vehicle- I've never seen the 350D in a pickup.

Anyway, the vacuum valve has 2 purposes- the wired switch signals the lockup torque converter, and the vacuum switch signals the transmission shift modulator. I'd bet a paycheck that any of the switches that fit will work. There may have been different calibrations depending on whether it was in a pickup or a Delta 98, but unless you're using it very hard you probably won't notice any difference.

 

Thank you, 350D engine was on Chevy C10 pick ups between 1978-81 and from 1982 onwards it was replaced with 6.2D engine.
My pick up has gone through quite complete overhaul and now almost finished with that work...

 

The valve you seek wasn't used on that many of the 5.7 or even the 6.2's. Vast majority of the cars that got the 5.7's got some flavor of the 200 transmission which just had a TV cable, no vac so it wasn't needed. Pickups in the 5.7 era I don't think were that common but was where they used a 350 so that is why they came up with that vacuum dodad.

I think a couple of the cars maybe had a towing package where you also got the 350 but I think word got out pretty quick that these things didn't have any power so I don't think people were ordering the towing package. When the 6.2 came out I think a lot of those ended up with 700r4's behind em so again just TV cable, no vacuum. It would have just been if you got a 400 you needed the vacuum and with no turbo are you really gonna haul that much?

I'm no expert on the pickups but one reason they were not real common is I believe the diesel was only available in the 1/2 ton 2wd. The 2wd eliminated anywhere it ever snows or any kind of farmer or rancher that has to ever leave the pavement. The only 1/2 ton also eliminated anyone that was really wanting to do real work with a truck so pretty narrow market and that was before the word got out about all the issues they had.

 

I didn't think any of the trucks got a locking converter till the 700r4 which was like 83ish? And I didn't think any of the trucks especially diesel got any sort of ECM till EFI for the gassers in 87 and then the 4L80e in what 91? Again I don't know the trucks that well.

 

TH350 had the first locking converter. It was only a year or two before the 700r4.