1970 CST Project Needs Assistance
 

I have searched the forum over and have yet to find a solution to my issue. I have seen lots of posts that do a good job on the A/C and heat vacuum lines but I have not been able to locate one that can help me layout how the engine and transmission vacuum lines run.

I have a 1970 Chevy CST, all factory with a 350 and TH350. I have completely broken down the truck and rebuilt everything over the course of 5 years. If there is anything I have learned, it is what a moron I was to not lay out the vacuum line schematics before I started (I also hate to stop and ask for directions on road trips).

So what I am needing is either a really comprehensive set of pictures or a volunteer here in North Texas that will let me come pick apart their engine bay to make my own (I will bring the beer). I just got the truck back from paint and body and I am very anxious to light it up and get it rolling again.

Let me know if you can help. Thanks in advance.

Re: 1970 CST Project Needs Assistance
 

Please don’t take this wrong!
I mean no offence!
Why is it that people ask a motor related question but post a pic of anything besides the motor?
Sure it’s a nice looking truck but a pic of the motor would do wonders.
You might not need much or possibly anything.

And how about some more engine info.
Stock or modded?
Fresh rebuild or used slightly?

Re: 1970 CST Project Needs Assistance
 

Ok, good point.

I think when you will see the pics that they are of little help at this stage. As I said, I have been working on the complete rebuild and am not to the stage yet where the Carb is on the engine (hence the request for guidance on how the lines run).

Not sure a picture of that provides any insight. But, here you go.

Re: 1970 CST Project Needs Assistance
 

It’s a start!
Stock intake with quadrajet I suppose.
Do you have power brakes?
That tubing back by the dip stick is for the trans modulator. Plugs onto a vacuum tree behind the carb.
Is the motor a fresh rebuild?
What distributor are you going to use?

Re: 1970 CST Project Needs Assistance
 

Correct. Stock intake, Rochester quad, power brakes, no cruise, stock non HEI distributor.

Re: 1970 CST Project Needs Assistance
 

Bunch of possible links for engine pics here.



https://www.google.com/search?q=1970...XB5DyoQ4dUDCAY

Re: 1970 CST Project Needs Assistance
 

BTW, beautiful truck! The good thing about these old Chevy trucks is that there are not very many vacuum hoses.

1) Power brake and TH350 take direct or "full" manifold vacuum. Typically some kind of port near the rear of the intake.
2) Distributor takes "ported" vacuum. I know where it is on a Holley, but not sure about the Quadrajet. Probably somewhere in the side of the carb.
3) PCV system (yes, you need it, it's awesome, and while it helps emissions, it helps you, too). Frequently it's a larger hose barb on the lower part of the carb (at least on a Holley). That goes to a 3/8" hose connecting to the PCV valve in a grommet in one of your valve covers.

Maybe not perfect, but maybe enough to get you started and then the other guys can shoot holes in my story where I've screwed up.

Re: 1970 CST Project Needs Assistance
 

Thanks Matt.