Overheating?

[snakesaway]

Ok thats very interesting see the picture below. You will notice there is a small black pipe coming off the carby on the right hand side this is the vacuum advance pipe does this look right to you.

Thanks Andrew

[DanEC]

Originally Posted by snakesaway

Ok thats very interesting see the picture below. You will notice there is a small black pipe coming off the carby on the right hand side this is the vacuum advance pipe does this look right to you.

Thanks Andrew

That larger black hose coming off of the right side, rear area of the carb is usually for a PVC setup or valve cover brearther - something like that. The full time vacuum source you should hook to your distributor is under the front bowl, coming out at an angle and currently capped.

Not completely sure but I think the upper port on the right front side of the carburetor and fuel bowl is a ported vacuum source. You can check it with the engine at hot idle and see if it reads the same as your manifold vacuum. I doubt that it does and I would not use that for the distributor.

Hope this helps a little

[cycleguy55]

Originally Posted by DanEC

The full time vacuum source you should hook to your distributor is under the front bowl, coming out at an angle and currently capped.

Agreed - in the photo you can see the end of the black cap sticking out a bit from under the primary fuel bowl - that's a manifold vacuum port. Just remove that black cap and connect the vacuum line which is currently connected to the timed / ported vacuum fitting on the side of the metering block. Don't forget to cap the timed / ported vacuum fitting on the carb that the vacuum hose is currently connected to. I believe both ports take 3/16" hose.

You'll find the idle speed will go up and the idle will most likely be a bit smoother after switching from ported / timed vacuum to manifold vacuum.

I used manifold vacuum for my connection and had to adjust the idle speed screws to drop the idle by about 200 RPM after I made the switch. Make sure the engine is fully warmed up and off fast idle before you make any idle speed and/or mixture adjustments.

Originally Posted by DanEC

Not completely sure but I think the upper port on the right front side of the carburetor and fuel bowl is a ported vacuum source.

I checked a Holley diagram and confirmed the upper port on the primary metering block is a timed / ported vacuum source.

[snakesaway]

Dan and Brian thanks guys for you input looks like I have some testing to do on the weekend. Will be interesting to see what I find out.

Thanks again Andrew

[DanEC]

Good luck. No promises, but since you have vacuum advance there's a good chance changing it over to manifold vacuum could make a noticeable difference in engine temps in traffic, at idle and slow to moderate speeds. It's an easy to do change also. If your engine is a bit weak and lumpy at idle, as Cycleguy55 mentioned it will also smooth that out a little due to the greater timing advance and make normal starts from a stop a bit easier.