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OK, this is a judgement free zone, right?
Being that this is my first carborated car, I am years behind on the learning curve.. Heres whats going on
I have a 78 L48, she came with an Edelbrock performer intake as well as an Edelbrock carb.. While working on the car we realized several issues with the Edelbrock, so its gone. In its place, a gifted Holley 4160 600CFM 80457 Carb... Hooray! Im in the Holley Club!
OK, thats where the fun ended.. I realized that after i got the old carb off, scraped at old gaskets for an hour, got my new gasket on and holley mounted, that I had no f'in idea what to do from there. I hooked up the choke, hooked up dist. vacuum, and gave my best uneducated guess at hooking on trans/throttle cabes/springs (this is why i said dont laugh!! )
If this looks correct to everyone so far, which i doubt it does, I have a few more questions..
Where does my brake booster get hooked into?
Where does my manifold vacuum line get hooked in?
I know i still need to hook up the fuel line - thats a problem for another day.
Thanks for being gentle, and type slow so I can keep up!
ThoughI'm a newbie to Corvettes, you're in my wheelhouse so a few tips to get you going (by picture)
Pic #1 - You have your vacuum advance on a ported vacuum source. Move it to the nipple under the front bowl (visible in pic 2....timing will be required)
Pic #4 _ The big nipple under the secondary diaphragm is where you want to connect your booster hose (it's manifold vacuum)
Fuel hose to the banjo fitting and fire it up!
OK. so once i move my vacuum advance to under the front bowl, do i plug the ported vacuum spot?
When i was looking into the port under the secondary diaphram, people said that was the PCV and not to connect the booster there which is why I avoided it - but if you say its good 2 go, ill give it a shot once i buy a longer vacuum line!
The brake booster hose should hook to a fitting between the back of the carb and the distributor. I would not hook the pcv and brake booster to the same fiting. You might have to put a spacer with a fitting under the carb.
Unfortunately, that model doesn't have the big fitting under the secondary bowl it's the one under the diaphragm. PCV and booster should be from separate manifold sources, so yes you can use the big nipple for PCV and a fitting on the manifold for booster. There are vacuum trees available if your intake doesn't have one. Cap all unused vacuum nipples.
Last edited by Its_hers; Oct 13, 2018 at 08:21 PM.
Big vac port on top if intake. Has vacuum for headlights-heater and what looks like vac line for auto trans. You could tee the brake booster or pcv there.
Big vac port on top if intake. Has vacuum for headlights-heater and what looks like vac line for auto trans. You could tee the brake booster or pcv there.
Originally Posted by Its_hers
Unfortunately, that model doesn't have the big fitting under the secondary bowl it's the one under the diaphragm. PCV and booster should be from separate manifold sources, so yes you can use the big nipple for PCV and a fitting on the manifold for booster. There are vacuum trees available if your intake doesn't have one. Cap all unused vacuum nipples.
just to make sure im hearing everyone correctly - is this what yall are talking about?
Also, do my connections look ok with the spring/throttle cables and such?
the PCV hose on the drivers side cover connects to the large open port under the secondary diaphragm . Did you get the instruction manual with the carburetor? https://www.jegs.com/InstallationIns...0-0-80457S.pdf
Good news, just got the new vacuum tree and holley fuel line fitting for the carb, going to mount everything up this evening and ill post picture for future holley transplants who have the same question!
OK. as promised here are the pictures from final install. I got her started about 20 minutes ago, now its on to learning how to tune a carb!!
The manifold vacuum tree i ended up purchasing was Right Stuff Detailing Vacuum Fittings IMF6707, and then went to the local hardware store to get a female thread adapter to fit my brake booster line on to (so i have brake booster, trans, and headlight vacuum on the same tree). Moved PCV to passenger side and then put my fuel line on (Holley part 26-29). Fired right up.
The vent on the passenger side should be removed otherwise you are defeating the purpose of the PCV.
^ good catch! You want the PCV to introduce vacuum in the oil chamber which causes air to be pulled in on the vent from the other side of the engine. By having a vent/breather on the same side of the PCV, the vacuum only exists really on that side, and within the valve cover.
The vent on the passenger side should be removed otherwise you are defeating the purpose of the PCV.
Originally Posted by AboveTheLogic
^ good catch! You want the PCV to introduce vacuum in the oil chamber which causes air to be pulled in on the vent from the other side of the engine. By having a vent/breather on the same side of the PCV, the vacuum only exists really on that side, and within the valve cover.
Not sure I follow, gents. I moved the vent/breather to the driver side valve cover, and the PCV got moved to the passenger side valve cover, so they are not on the same side as one another.
Not sure I follow, gents. I moved the vent/breather to the driver side valve cover, and the PCV got moved to the passenger side valve cover, so they are not on the same side as one another.
Is your oil filler cap on the passenger side valve cover sealed or vented? If vented you are defeating the function of the PCV.
Btw, most of us are uncomfortable with rubber fuel line between fuel pump and carb. That is the pressure side of the pump, and we don’t like seeing nice Corvettes burn to the ground.
Help with a Holley
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