1976 455 Vacuum help!
#1
1976 455 Vacuum help!
Just picked up a 76 98 Regency. The old owner (or one of them?) swapped out the Rochester for a nice Edelbrock, and in the process, got rid of most of the vacuum lines. Anyone have a good diagram? Vacuum routing confuses the hell outta me. I WAS winging it with a diagram I found online, and then I found out that diagram was for a 350.
#2
The carburetor is an Edelbrock 1400. I'm having trouble determining which port is which in following the diagram I got from Autozone. I found the one that is manifold vacuum, but the stock Rochester seems to have 3 ports, while the Edelbrock only seems to have 2? Also, my engine doesn't seem to have the thermal control valve located by the thermostat spout? I'm so confused hahaha.
#3
The carburetor is an Edelbrock 1400. I'm having trouble determining which port is which in following the diagram I got from Autozone. I found the one that is manifold vacuum, but the stock Rochester seems to have 3 ports, while the Edelbrock only seems to have 2? Also, my engine doesn't seem to have the thermal control valve located by the thermostat spout? I'm so confused hahaha.
#4
Well, first, the diagram (that didn't make it into your post) assumes the factory carb. It's unlikely the aftermarket carb has all the same ports. Second, is the intake even stock? Post a photo of the engine. Third, spend the money and buy a factory Chassis Service Manual, which as all the correct factory info. You'll want this book if you ever do any real work on this car.
#5
On your Edelbrock carb the 2 small ports on the front are, passenger side is ported vacuum, drivers side is manifold. The larger ports front and back are both manifold vacuum. The PCV needs to be hooked to the front large port.
#6
Yeah, I was able to pull the owner's manual for the carb up in my store (work at a True Value parts store). While the manifold vacuum one makes sense with the Olds diagram, I didn't know if the other side was ported or something else. And then the Edelbrock is missing the valve-lookin' thing coming off of the front of the Rochester. Would I just tap that into the ported lines?
#8
#9
#16
What manifold are you using for this carb? For the power brakes, as I mentioned above there is a port on the bottom back center of the carb that you will need to add a nipple to. See the instructions link, there is an embedded picture of it on top right of the picture on the first page.
http://static.summitracing.com/globa...Carburetor.pdf
http://static.summitracing.com/globa...Carburetor.pdf
#17
Two, the vacuum BREAK is part of the original Qjet carb and is not used on the Ebrock carb. The hose goes directly from the vacuum diaphragm to a port on the Qjet. That hose shouldn't even exist anymore. Ignore it.
Also, stop trying to use a factory vacuum diagram to connect your aftermarket carb. You can't. The factory diagram is for the factory carb, period. The aftermarket carb is different and may or may not have all the connections you need. This is the fundamental problem with an aftermarket carb, especially on a mid-70s car with lots of unique emissions control connections. Either understand how your new carb works and connect it as needed or go back to the factory carb and connect it per the diagram.
#18
Once you put an aftermarket carb on your engine, pretty much all your factory vacuum diagrams go out the window. If you're not familiar with what is controlled by vacuum and where it needs to come from, you have to understand that first, and then you'll feel a little more comfortable not "going by the book".
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