I use the rear port on the manifold to work my vacuum guage inside the bird, it can be used for other things as wipers etc or like you say just plug it off if you don't need it.

-Gary Burnette-

Brian:

That port has a 3/8" pipe thread.

John - "The Hoosier Hurricane"

I ran my power brakes (OE) to it.  Works fine for that.

Ron Grove

Wauconda, IL

Brian - Be sure and check your base spacer and gasket against the Demon Jr. primary / secondary bore sizes. The Demon base plate bore is bigger than the 600 cfm Holley.

Also - be watching the float stability - my outfit had Viton needle and seat assemblies that just didn't care for the local gas - very sticky and a pain in the a$$ while trying to tune. I changed them out for steel needle and seat assemblies and that finished off the problem immediately.  From Summit a pair of .130's is P/N 6-515-2 about the best price you will find mail order. 

 
 Steve Metzger       Tucson, Arizona

OK - Thanks for the tips.

I'll buy the 3/8" plug for the manifold & also the 0.130 steel needle & seat. I have to buy a fuel inlet fitting anyway (didn't realize the reman ddn't come with one). On your T-Bird did you stick with stock primary jets & secondary spring?

Brian - 56 T-Bird

Woodinville WA

Brian - I also had to go on a search to find the proper fitting to "hard line" the 5/16 steel fuel feed up from the fuel filter. In the end - I had to do away with the carb filter at the fuel inlet port. I'm using the big paper element "Delco" filter in the pressure line so ....I'm not figuring it to be a problem.

The Demon internal throttle return spring is not well suited to the Fordo "kick-down" springs in the throtttle assembly - still working on that one.... It needs a better set-up altogether - but I haven't gone there yet. Finally, to get it out on the road - I stuck a bolt, nut and washers in the slot to stop over-travel for now.  

I'm having a problem with this computer this am - will try to get you a picture

 
 Steve Metzger       Tucson, Arizona

Will try again with the pictures

this is with the old 600 Holley - but shows the filter and pressure gauge

I put a bigger 428 fuel pump on there - with no vacuum pump so that part of the plumbing changed

 
 Steve Metzger       Tucson, Arizona

Ok - so now that the photos will up-load.....for tuning - I will explain - I usually make my outfits run lean and work up from there....others have their way I have mine. The tuning has to match the dizzy - so get your curve in there first. I used 10° static / 26° centrifugal / all in by 2600 rpm. I use live manifold vacuum advance at idle - some don't - but disconnect and plug to set timing.

Set idle mixture with vacuum gauge - I think its best not to have the open style of carb spacer on a street motor - so it will "answer" the screws side for side.

I used the Holley "Black" secondary spring - stiffest in the pile. The Demon primary is a huge hole with nice boosters and from what I can see - tends to act like a big two barrel most of the time. It doesn't even need the seccondaries to feed a 312 with standard gearing for most use.

Primary jets went down one - needle and seat set-up as above.

The float level on a Demon is a wonderful tool - it changes rich/lean very nearly linear across the scale. Because the bird auto starts in second - you've got to creep it up until she accelerates cleanly - otherwise bogs a bit. 

 
 Steve Metzger       Tucson, Arizona

Great photos & thanks again for the tips. Very clean looking. I guess I have to break open the carb to be sure, but believe iI read in searches it comes with #58 primary jets out of the box. I also would like to start a bit lean & go from there. Was that your experience also? Did you try the ported & full vacuum ports for the dizzy  & decided it ran better staying with full?

Brian - 56 T-Bird

Woodinville WA

My experience - starts at '64 in high school - has always been to run them with live manifold vacuum at idle. Ford supplied them with ported and some like that set-up. Ted for instance...

The live vacuum makes the idle speed come up - but the idle water temp goes down. It also provides for some very high vacuum readings at idle - that you won't get when you are hooked up to the ported. Wise men have told me  - whatever works best for you  - use.

Keep in mind that when the engine comes off idle - both systems will behave the same........

Running live manifold vacuum and no exhaust crossover valve has made my outfit run pretty cool - in fact I'm about to go up to the 180° thermostat (factory spec is 157°). I don't like the wide swing from winter to summer and I'm trying to narrow it down.

 
 Steve Metzger       Tucson, Arizona