Carb Riser vacuum port and other vacuum questions

[TexasEd 188]

There is a very large port on the car spacer/riser.  What is this for?  

To get my car started I am going to cap it and put a clamp on it because I can't find a tight enough cap.  

I was missing my manifold vacuum riser after getting the manifold blasted so I got a new one installed with a single line going to the C4 transmission and a cap on the bigger port.  I have the larger port on the back of the carb going to the PCV and the metered port on the front of the carb going to the distributor.  I don't have power brakes.

I know I'll have to hook up lines for the AC and heater vents later, but just trying to start it for now.

 

[barnett468 418]

pcv hose.

[TexasEd 188]

Thanks, the hose I'm using does not have enough give to get over that big port easily.  I'll try and stretch it a little to see if I can get it on.

 

[jholmes217 65]

I just buy some fuel line hose from your local parts dealer.   I used 3/8 hose and cut to fit.  They have elbows and adapters if you need it to make a sharp curve or change sizes.

[TexasEd 188]

The OD on the port is the same as the OD on the hose that connects to the PCV.  I think it would take a hose as big as the heater core hose to connect to that port.

When I got the car back from my dad and bother they had taken the riser off.  

[LoneWolf2U 136]

Normally the 3/8 fuel line can e used to connect the pcv. Having the spacer plate removed is costing you bottom end power and maybe a fuel over heat trouble as the carb sitting directly on the intake. 

[TexasEd 188]

That's why I put the spacer back on.  I do believe it was overheating the gas.  The 3/8" fuel line does connect to the port on the back of the carb but not to the one on the spacer.  Who knows if I have an original spacer but it measures pretty close to 9/16" in diameter.  If I used a hose that big it wouldn't fit on the PCV I have.

I will cap the port on the spacer.