[joem1021]

I'm trying to find a vacuum line diagram or just help would work. I have a 81 firebird formula with a 383. I just took off the stock intake and q-jet and replaced it with a torker II and a holley 650 dbl pumper. I just cant seem to remember where all of the vacuum lines are suppose to connect. I would appreicate any help or pics for reference. Thanks

[engineer]

diagrams are in your factory service manual. good practice to take photos or tape \ label lines with location points.

[joem1021]

I usually take more pictures than I need to. I thought I took pictures of this. I guess this time I was just to excited about new parts.

["QUICK-SILVER"]

Hook vacuum advance to front metering block on passengers side of carb.

On front of base plate/right side should be full time vacuum port. Use a T and hook up modulator valve and AC/heater duct hose.

PCV should be centrally located under carb, so hook it to back/center base plate.

Power brakes doesn't need to be hooked with PCV, since PCV flows at idle there may not be adequate vacuum for power brakes to work right.

Use a fitting in intake to run power brakes. If it doesn't have a place in intake and you can't drill your own, get a spacer plate with a fitting or use a plain spacer and drill and tap it for a fitting.

If you have to use a spacer with a fitting, you can move brake to back of carb and have PCV coming out of front on spacer.

[joem1021]

my vacuum advance is on the drivers side rear metering block. does that make a difference? thanks for your help

["QUICK-SILVER"]

Originally Posted by joem1021

my vacuum advance is on the drivers side rear metering block. does that make a difference? thanks for your help

Evidently carb has been converted to four corner idle using a front metering block, so it may not get proper ported vacuum on rear block.

The vacuum passage, for the front metering block, starts right above the right front throttle blade. Primary part throttle opening (cruise) provides vacuum to passageway.

If vacuum passage on rear block works ported, secondary throttle blades would have to partially open to provide vacuum to distributor. With secondary throttle opening vacuum starts to drop.

Anyway back to your question, for vacuum advance to work properly, it needs to be hooked to primary (front) end of carburetor, for cruising. Vacuum advance is for cruise only. Vacuum in intake drops near WOT and vacuum advance doesn't work.

Hope that makes sense.

[joem1021]

I've never run this carb before. I also noticed that it does not have a power valve in the rear metering block, it doesnt even have a place for one. I'm using this on a street car. Maybe its not the best choice. I was told it ran great though

[joem1021]

I've got a couple pics on hand of the carb. i can take a couple more if you can help. any info would be helpful.

http://s290.photobucket.com/albums/l...h_newcarb1.jpg

http://s290.photobucket.com/albums/l...h_newcarb2.jpg

["QUICK-SILVER"]

Whats the list number on the front of the air horn and does it have idle mixture screws in the rear metering block?

The 4777-? 650 DP's are usually good performing carburetors on the street, excellent throttle response and quick revs.

[joem1021]

I'm not sure the rest of the numbers I will find out tonight. I think it only has one metering screw in the pass side rear metering block

["QUICK-SILVER"]

Originally Posted by joem1021

I'm not sure the rest of the numbers I will find out tonight. I think it only has one metering screw in the pass side rear metering block

Better check that close, there's no such thing as one, It will be none or both sides.

On an unmodified factory carb rear metering block, The holes where mixture screws would go, "could" be there, just not drilled out for use.

Is there a place to hook a vacuum hose on the passenger side front metering block? Can't see it in pic.

May have to pull a bowl and see if metering blocks have gotten mixed up, switched front to rear, rear to front.

[joem1021]

upon closer inspection the metering blocks were switched. There are mixture screws in one metering block but there missing from the other but it is drilled out. I ordered new mixture screws this morning and will install. I checked the rest of the numbers on the front and it reads 4777-13. i dont know if that helps at all. I hooked a few of the vacuum lines up yesterday. I've got a line from a vent in the drivers side valve cover that I'm not sure where to run. I'm assuming that it needs a full vacuum conection.

["QUICK-SILVER"]

Originally Posted by joem1021

upon closer inspection the metering blocks were switched. There are mixture screws in one metering block but there missing from the other but it is drilled out. I ordered new mixture screws this morning and will install. I checked the rest of the numbers on the front and it reads 4777-13. i dont know if that helps at all. I hooked a few of the vacuum lines up yesterday. I've got a line from a vent in the drivers side valve cover that I'm not sure where to run. I'm assuming that it needs a full vacuum conection.

4777 confirms it's a 650, can't find anything specific on -13.
The holes for mixture screws are in most rear metering blocks, the very bottom of the hole usually doesn't go all the way through. Blow through it and make sure it is a metering block for four corner idle, before you try to put a mixture screw in, it may just be a normal rear metering block that "looks like" it should have mixture screws.

PCV is a crankcase vent valve, 3/8 hose should fit, it does get full vacuum.
Go back to post 4 about concerns with PCV and power brakes.