Break booster vacuum to front of intake??? Will it work?

[Eltoroloco]

Recently I’ve rebuilt my 350. It has a performer rpm intake with a quick fuel 650 carb. I’m hooking up all the vacuum lines and had a question about where to run the breaker booster vacuum line. From what i read you need to come off the intake behind the carb. I put a plug in it before I started reading up on it. I have a vacuum port on the front of the intake that’s not being use. All it needs is a fitting. My question is would it be suitable to run the break booster?

 

[Dmack]

Could be wrong, but the booster should be fine as long as the vacuum port use large enough. The only possible issue I can think of is leaning out the cylinder that the front port is in, assuming you are saying it is in a runner and not right at the base of the carb in front.

 

[Eltoroloco]

It’s on the right next to the thermostat

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[idahovette]

Don't think that's vacuum, it's in a coolant passage.

 

[Frankenchevy]

It’s on the right next to the thermostat

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Yep, everything in the front area of the intake manifold is for coolant. One to the heater core and one to the water pump.

Here’s a shot of the routing of heater core hoses. Yours may be slightly different, but going to the same areas. The larger hose coming from the heater core goes into the passenger side of the intake manifold, the smaller hose from the heater core goes to the water pump, then water pump to driver side of intake manifold.

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I also think you want your t-stat above your water neck gasket before installing the water neck.

 

[Eltoroloco]

When I took it apart I had one hose from the heater core going to the intake and the other came from the water pump to the heater core. I may need to change things up now

 

[Eltoroloco]

Yep, everything in the front area of the intake manifold is for coolant. One to the heater core and one to the water pump.

Here’s a shot of the routing of heater core hoses. Yours may be slightly different, but going to the same areas. The larger hose coming from the heater core goes into the passenger side of the intake manifold, the smaller hose from the heater core goes to the water pump, then water pump to driver side of intake manifold.

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I also think you want your t-stat above your water neck gasket before installing the water neck.

My water pump only has one outlet if I’m not mistaken

 

[Frankenchevy]

My water pump only has one outlet if I’m not mistaken

You’re right. My vortec is different. I think on my old setup the larger heater hose went straight to the radiator. An internet search for ”gen 1 sbc heater hose routing” will be your friend here...

Either way, the vacuum source for your brake booster is either a large nipple on the carb base that provides full manifold vacuum, or the plugged bung on the back of the manifold.

 

[Craig 85]

It should be the port behind the carb opening on the runner for the #8 cylinder, upper right of the pictures. The ones near the thermostat are for coolant. Performer 7101 on the left, OEM on the right.

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[Rusty Nail]

See above.

 

[MikeB]

That port on the Edelbrock manifold is far enough forward that a vacuum hose fitting will interfere with the Holley's rear float bowl. You can possibly use the port on the back of the carb, if it has one; or worst case you can use a carb spacer.

Silly place for Edelbrock to put the port, considering the popularity of Holley carbs. It was enough to make me start using Holley/Weiand manifolds years ago.

Edelbrock Performer RPM:

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Holley Speed Warrior

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[75Monza]

Yep, everything in the front area of the intake manifold is for coolant. One to the heater core and one to the water pump.

Here’s a shot of the routing of heater core hoses. Yours may be slightly different, but going to the same areas. The larger hose coming from the heater core goes into the passenger side of the intake manifold, the smaller hose from the heater core goes to the water pump, then water pump to driver side of intake manifold.

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I also think you want your t-stat above your water neck gasket before installing the water neck.

Most of the intakes I've ever seen sbc are machined for the t-stat to sit down in the manifold with the gasket above it, not saying there are not any out there that are different. Only thing I've changed doing over the years with t-stats is making my own bleed hole since they quit putting the little bleed port on the t-stat long time ago.

 

[idahovette]

Yeah 1/8 " drill bit and you got an instant bleed hole.

 

[Eltoroloco]

That port on the Edelbrock manifold is far enough forward that a vacuum hose fitting will interfere with the Holley's rear float bowl. You can possibly use the port on the back of the carb, if it has one; or worst case you can use a carb spacer.

Silly place for Edelbrock to put the port, considering the popularity of Holley carbs. It was enough to make me start using Holley/Weiand manifolds years ago.

Edelbrock Performer RPM:

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Holley Speed Warrior

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My quick fuel carb is essentially a holly carb. I ordered a low profile 90 but I’m pretty positive it will still hit. I’ll order a spacer and that should be fine. They put that vacuum port in a really bad spot. I probably would have ordered a better design of an intake but mine was free lol

 

[idahovette]

Free is good!! Just some finagaling and you will get it.