305 to 350 same vacuum diagram?

[Harmon]

I've posted about lack of power in my 1986 c10. The truck had a 305 but later received the Goodwrench 350. I can hear what appears to be vacuum hiss so I think I should re do the vacuum lines as it looks as someone has messed with it.

My question is the vacuum diagram the same for a 305 as it was for a 350?

[Axle]

For your circumstances, yes. I am assuming nothing was changed other than the engine.

Alex.

[Harmon]

I found a diagram that is labeled YDR. Would that be the one I would need?

[Axle]

Look at the sticker on your core support if you want to reference a label printed in a book. There are too many variations of emmisions label to just pick one.

If yours has no sticker or you are completely unfamiliar with this, make your own roadmap on paper with what is currently on your truck, and just recreate that.

Alex.

[Harmon]

Mine has no sticker. I know some of the vacuum lines are missing too, thus me trying to find a diagram.

What a nightmare this is lol

[geezer#99]

Break out your camera and take a pic or two!!
What tranny?
What exhaust?

[RUN GMC]

I just replaced three vacuum lines tonight on mine in the auto zone parking lot......broke a plastic pot behind the motor that was a 3 way replaced that with 3 way tee.......well my motor picked up better idle, brakes got a little firmer, and the trans shifted better.....tomorrow in daylight i will assess the rest of my vacuum lines for replacement.............

[Harmon]

Here is a few pics of my engine bay.

[geezer#99]

Looks like my old 84.
I don't see a tv cable so assume it's a standard tranny.
All you need to do is pull each hose off and check it's not cracked or rotten.
The multi hook ups on the thermo housing are prone to leak.
Just check each hose one at a time and repair as needed.
Search google 'images' for vac diagrams if needed.

[Axle]

Does not look too bad. Just go through one hose at a time and replace it. Pay attention to any discs that are in the vacuum line and put them back the same way (ie: that one a couple inches from the vacuum switch in the thermostat housing) they are one-way valves aka check valves. They are either marked by color (black on one side, another color on the other) or they have a flat side and a curved side (same color).

Pay attention to how snug the fit is on the molded vacuum hoses that go into that thermostat housing switch, if it is loose, remove it, and simply replace with individual vacuum lines, which you can tywrap in pairs and together as a bundle to maintain orientation of the lines.

And your valve covers are on the wrong side. PCV should be by itself so it doesn't end up sucking air from the oil filler hole and not be as effective. Oil filler goes on the passenger side, towards the front of the truck. And the PCV valve hole is towards the front of the truck as well.

Alex.

[Harmon]

Thanks!
It is a auto trans.what is the tv cable and location?

As far as the the valve covers I need to reverse direction and swap each one to other side? Then I need to hook a hose to rear of passenger side of air cleaner to the valve cover?

[geezer#99]

Originally Posted by Harmon

Thanks!
It is a auto trans.what is the tv cable and location?

As far as the the valve covers I need to reverse direction and swap each one to other side? Then I need to hook a hose to rear of passenger side of air cleaner to the valve cover?

Tv cable or kickdown cable is hooked to your carb under the throttle cable. I can't see it in your pics.
Leave the covers where they are.
You got the breather tube in the right place. If you swap them you won't.

Here's a couple pics of my old 84.

[Axle]

You keep everything on the side that it is, breather tube stays in the passenger side cover.
PCV in the drivers side cover. The cover with the filler hole goes on the pside, the cover with one hole goes on the d.side.

Alex.