Holley 4175 Tuning - HELP!!!

[igasper10]

Hey all, I finished rebuilding & installing my Holley 4175 650cfm vacuum secondary carb on my 74' project. I just have one question that I can't seem to get a straight answer on. There's a small hose fitting coming directly off the side of the primary metering block. All of my hoses are hooked back up to the carb in the right places (I think). I've seen pictures of this carb mounted with a hose going to it, and pictures where its just open. Anyone know how it should be???

Ian -

 

[1BAD80]

That is the timed port for the vacuum advance on the distributor.

 

[igasper10]

WHISTLING???

Thanks for the answer!

Also, whenever I give the throttle a good kick, something whistles. It sounds like its coming from the carb, but I'm not sure. Anyone know what it could be??? Would it have anything to do with the distributor advance port being open???

Ian - ;help

P.S. Does anyone know if there's a place online where I can get a good exploded view or drawing showing where all hoses for my carb (Holley 4175 650cfm) go? I'm flying blind as far as hose locations.

 

[Stallion]

Re: WHISTLING???

Thanks for the answer!

Also, whenever I give the throttle a good kick, something whistles. It sounds like its coming from the carb, but I'm not sure. Anyone know what it could be??? Would it have anything to do with the distributor advance port being open???

Ian - ;help

P.S. Does anyone know if there's a place online where I can get a good exploded view or drawing showing where all hoses for my carb (Holley 4175 650cfm) go? I'm flying blind as far as hose locations.

Here's another recent carb whistling thread.

Good luck!!

TR

 

[JohnZ]

Re: WHISTLING???

Also, whenever I give the throttle a good kick, something whistles. It sounds like its coming from the carb, but I'm not sure. Anyone know what it could be??? Would it have anything to do with the distributor advance port being open???

Ian - ;help

Yup, if you have an open vacuum nipple on the carb, that's where the whistle is coming from; any unused nipples must be capped, or you'll have the whistle (and a vacuum leak).

 

[Stallion]

But shouldn't there be a vacuum hose connected to it, John? Otherwise, why else would it be there? What is it's purpose this vacuum nipple?

 

[igasper10]

NO MORE WHISTLE!!!

Thanx for your help on this one! I called Holley and got a diagram with all hose routings for my carb & engine application. Its running great! Tuning went well after that with a vacuum gage. I think my pump discharge nozzle is too big/small though, because I get a little hesitation when I stomp on the gas.

ian