250 vacuum lines- - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Grimm76 · 02-13-2013, 10:28 PM

Hey:
I located a used motor out of a '72 Camaro and it got delivered today. It came with a smog pump and a total spaghetti of vacuum lines. More than I encountered when I tore into the truck the first time (old dead motor is in pieces in the bed).

My question is: is there somewhere on the forum that outlines all these different vacuum lines and what I need vs. what I can junk? I took the smog pump off and want to get this cleaned up so I can stab it in. Can someone point me in the right direction, please?

JAMESCHURCH13 · 02-13-2013, 11:51 PM

Really depends on if you have a smog inspection/what year your truck is/what you use your truck for.

D13 · 02-14-2013, 06:53 AM

Need to know what it's going in to.

Absolute minimum, vacuum line to distributor.
TH350 or 400 auto trans, vacuum line to trans.
Power brakes, vacuum to brakes. These are the most likely things in an early truck.
A/C doors run off vacuum but not likely present on an L6 truck.
Easiest thing is to get a diagram for the truck, and hose up accordingly.
Do you need smog? Evaporative emissions? PCV? Thermac air cleaner? Exhaust heat? EGR?
BTW if the motor is California smog out of 72 or earlier, there is a certain resto crowd that looks for correct smog pumps.
Do le't pretend

Grimm76 · 02-14-2013, 12:49 PM

250 six going into a '76 C-10 2WD. There is a vacuum canister on the inside fender well with three lines, two of which were not connected. We got a rebuilt 2 barrel from Langdon's Stovebolt and put that on, and after some tweaking we got it through smog test (no smog pump on at that time). Shortly after that, the water pump failed, the block boiled dry, and cracked. Hence the search for a replacement 250- figuring a direct replacement would be an easy bolt-in.

The new(er) engine arrived yesterday- with several more vacuum lines leading from the block, the head, and to a functioning 1 barrel carb. All stock. Most of the fittings on the block and head allow three or four separate hoses to be attached and there are also two small metal lines from the lower passenger side of the block, one to a four-hose fitting on the intake, and the other to a vacuum-actuated valve on the exhaust manifold (I never even know that one was on there till I tore stuff apart.)

No info whatever in my Haynes manual- any help appreciated!

No automatic trans- a 4-speed with granny low (SM465?) with no plans to change trans in the immediate future.

02-13-2013, 10:28 PM	#1
Grimm76 Registered User Join Date: Jan 2013 Location: Gladstone, Oregon Posts: 7	250 vacuum lines- Hey: I located a used motor out of a '72 Camaro and it got delivered today. It came with a smog pump and a total spaghetti of vacuum lines. More than I encountered when I tore into the truck the first time (old dead motor is in pieces in the bed). My question is: is there somewhere on the forum that outlines all these different vacuum lines and what I need vs. what I can junk? I took the smog pump off and want to get this cleaned up so I can stab it in. Can someone point me in the right direction, please?

02-13-2013, 11:51 PM	#2
JAMESCHURCH13 JamesChurch13 Join Date: May 2006 Location: Edwards AFB Sunny California Posts: 151	Re: 250 vacuum lines- Really depends on if you have a smog inspection/what year your truck is/what you use your truck for. __________________ *HG/FTW!!!* Current vehicle collection: 1968 Chevy C-10 SWB Fleet Side, 327ci, TH350 (MD) 1987 Chevy Dually Quad Cab, 427ci, TH400 2008 Buell XB12SS, 1203cc 2006 YZ450F Wheelie Machine! 1997 Suzuki Bandit 600cc And the Wife has some cars I pay insurance on and use to transport the kids!(01' Grand Cherokee and 06' Pontiac Grand Prix)

02-14-2013, 06:53 AM	#3
D13 Registered User Join Date: Feb 2007 Location: Memphis MI Posts: 1,851	Re: 250 vacuum lines- Need to know what it's going in to. Absolute minimum, vacuum line to distributor. TH350 or 400 auto trans, vacuum line to trans. Power brakes, vacuum to brakes. These are the most likely things in an early truck. A/C doors run off vacuum but not likely present on an L6 truck. Easiest thing is to get a diagram for the truck, and hose up accordingly. Do you need smog? Evaporative emissions? PCV? Thermac air cleaner? Exhaust heat? EGR? BTW if the motor is California smog out of 72 or earlier, there is a certain resto crowd that looks for correct smog pumps. Do le't pretend __________________ 1987 2 ton 1982 250/TH350 beater in progress Dad's 1981 3/4 L6 3 on tree posi and no options, awaiting restoration or scrapping Plus a mess o' tractors

02-14-2013, 12:49 PM	#4
Grimm76 Registered User Join Date: Jan 2013 Location: Gladstone, Oregon Posts: 7	Re: 250 vacuum lines-help please 250 six going into a '76 C-10 2WD. There is a vacuum canister on the inside fender well with three lines, two of which were not connected. We got a rebuilt 2 barrel from Langdon's Stovebolt and put that on, and after some tweaking we got it through smog test (no smog pump on at that time). Shortly after that, the water pump failed, the block boiled dry, and cracked. Hence the search for a replacement 250- figuring a direct replacement would be an easy bolt-in. The new(er) engine arrived yesterday- with several more vacuum lines leading from the block, the head, and to a functioning 1 barrel carb. All stock. Most of the fittings on the block and head allow three or four separate hoses to be attached and there are also two small metal lines from the lower passenger side of the block, one to a four-hose fitting on the intake, and the other to a vacuum-actuated valve on the exhaust manifold (I never even know that one was on there till I tore stuff apart.) No info whatever in my Haynes manual- any help appreciated! No automatic trans- a 4-speed with granny low (SM465?) with no plans to change trans in the immediate future.



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