Hi,

About 2 yrs ago I had my mechanic replace the tired 4180 with a 4160... which I thought was an 080457s.

Well I am trouble shooting a vacuum leak and have now become entrenched in the wild vacuum hose routing ride. I thought I had EGR valve leak, deleted it, and still detect a leak coming from that area.

To my surprise while poking and contorting my body around further, there appears to be an open PCV carb connection at the carb rear (closest to firewall.) All the 080457s manuals show this guy on the side (near elec. choke) which is blocked on mine (metal cover.)

I read the air horn - 80457-8 3109.

And I can't find a manual online at all.

Can I just plug that PCV port since I still have EGR plate in place?? There are 2 other capped connections on the front of the carb, smaller diameter.

Anyone know the primary difference between the -8 and the "s"??

I'd love to post pics, but my wife has her camera with her and my phone is useless for that stuff.

Thanks.

 

You have the aluminum version (0-80457SA)

Here's the pdf with the rear EGR port;

http://www.holley.com/data/Products/...7948-5rev3.pdf

Holley Performance Products 600 CFM Four Barrel Aluminum Street Carburetor*0-80457SA

 

Yep, you got it. Thanks!!

Was I correct that if the EGR plate is still in place with all vacuum sources routed to it I should cap all but the ported vacuum from carb (used for dizzy advance) ?

 

I use manifold vacuum through a restriction on my truck.
If you have capped everything looking for a vacuum leak, it may be that the EGR plate lower gasket has burned out.

You still need a PCV connection to keep from blowing oil out of everywhere.

You don't say what year truck, or type of engine.
Different years and GVW's have different connections and ports.

I have to keep my emissions in place for annual inspection.
My vacuum routing diagram is pretty complex.
http://www.flickr.com/photos/24183730@N03/2340584591/http://www.flickr.com/photos/24183730@N03/2340584591/ by http://www.flickr.com/people/24183730@N03/, on Flickr

 

'86 351W on an F250.

 

Yours may be similar to mine.
Do you still have a vacuum routing on your radiator support or drivers side valve cover?

A lot depends on how much of the emissions is still in use on your truck.

I know that my 460 doesn't want to idle without vacuum advance.
That's why I'm using manifold vacuum and the vacuum restriction that is incorporated into the thermal switch atop my thermostat housing. (per my diagram)

Have you tried reconnecting your PCV valve?
Definitely cap or connect any open vacuum ports.
With the engine running try spraying some carburetor cleaner in different places around the base of your carb.
It should be simple to find a leak this way.

 

Thanks for all the help. The vacuum diagram is still there, but damn it is hard to read. With the discovery of the open PCV connection on the back of the carburetor (I'm guessing the cap was cracked and fell off somewhere) that was the fix.

She's running again, and I saved all the EGR stuff I removed just in case. Now need to dial in the carburetor for some winter weather.

Did test further with some starter fluid around all fittings near carb/ main vac lines and didn't detect any further leaks.