Need vaccum diagram for chevy impala 1978 with 6 in line motor with 1 barrel carb. rochester mono jet

Yes we have lots Pennylee, and also a Service Manual.

https://www.google.com/search?q=vacuum+diagrams+on+a+1983+Chevy+p30+7.4

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Question edited for clarity and spelling.

Quadrajet is the carburetor made by Rochester. Vacuum information is in the link. More on the mages tab.

https://www.google.com/search?q=rochester+quadrajet+carburetor+vacuum+diagram

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You may need to advance your timeing by 1 or 2 decrees. But first get you a spray bottle with soapy water. If it will crank spray around the carb base and intake. If you have a vacum leak. Your engine will lug down. Showing where the vacum leak is. If that's not it. Your air and fuel screws on the carb. You screw them all the way in. Then out a quater turn at a time. Open your rear flap so all 4 are drawing air at the same time. And a just it for. There.

https://duckduckgo.com/?q=Vaccum+line+diagram+2001+chevy+impala+3800+v6&atb=v61-3_a&ia=images&iax=1

1979 chevy C1500
the vacuum setup varies,
by (california, Federal (USA) and export models)
where are you, or if in USA the under hood sticker shows if calif.or not.

if in usa, use the FSM (buy one used) or use alldata.com
on USA cars , (not sure starting year, this one is old) the vacuum
map is on the underside of the hood. (not not painted over,etc)

Yes, the engine will swap fine, for the vacuum lines Go to Autozone.com, become member, will give you repair manual,location of parts,diagrams.

this site has manuals but you have to pay a few dollars for them
http://www.carbkitsource.com/carbs/tech/Rochester/TwoJet-index.html

I don't have a diagram but I think the replacement carburetor may have come off an engine that had a governor which was activated by a plunger under the distributor plate. The vacuum lines went between the carburetor and distributor. Check to see if there is vacuum at one of the lines when the engine is runnuing. If there is just plug it off. A vacuum leak could be causing your idle problem.

it is in the housing where the fuel line enters the carb. unscrew and remove the input fuel line, then unscrew and remove the housing. take note of the direction of the paper filter you remove. here's a page with more info on that car. http://www.carburetor.ca/carbs/tech/Rochester/Quadrajet-index.html

Dist should go to rear of carb base but can also go to intake. large fitting at rear goes to brake booster. There should also be another large one for pcv valve.There other ports that supply vacuum to accessories options. Some ports on that carb are above throttle plate and only give vacuum at times when throttle is open. anything that needs full time supply should not be connected there.Block off all unused ports.