394 Choke Tube

[Guest]

Anybody had any luck finding a suitable replacement for the choke tube that is

pressed into the bottom side of intake manifold on a 63 394? 5/16 stainless too

small.Seems to be 11/32 and I have had no luck finding that.Also,how is the

original connection to the choke made?

[rocketraider]

Your best bet may be to find another manifold with a good tube. Olds (and all of GM) had a peculiar habit of using a lot of odd-sized stuff. The 9/32 hex interior screws are the ones that drive me nuts...

You've seen how the thing is made- a straight tube with a pressed-in 90 degree elbow at the bottom to prevent water from being sucked into the tube. The carburetor end of the tube connects to the carb with another short piece of curved tubing that is a slip fit into the manifold choke tube and has a flare nut to connect it to the carb choke housing.

It's possible that you could use the 5/16 tubing and then figure a way to expand it at the manifold openings to get a tight seal. You could use a flaring tool to make a lip at the carb end, then peen it into the manifold, and then do the same at the air intake end.

Just in case you're lucky enough to find one NOS, here's the part #s for the 394 choke heat tubes.

580765- choke heater tube, 61-64 except F85, J88

576409- choke heater tube elbow, 59-64 exc F85, J88

575499- tube, carb to manifold, 59-64 4 barrel carb except Pos Vent, F85 or J88

585656- tube, carb to manifold, 62-64 2 barrel carb exc F85, J88

Good luck!

[Guest]

My 394 had a rotted tube also...I believe most will...I used a drift punch and hammered out the broken ends that were still in the manifold...Then I used a piece of steel brake line...5/16, I think and as Rocker Raider said swaged [expanded] it out at the ends with a tool designed for refrigeration tube....It worked very well...Good Luck!

[Guest]

Thanks for the response guys.Thats kinda what I had in mind. One day it

will be as easy for us as it is for Chevy & Ford guys to get our hands

on new repro parts.Now question #2.The car in question is a 63 Super 88

4 door Holiday Sedan.Not the most desirable car but it was given to

my 17 year old by his Grandfather.It's straight as an arrow,no rust and

70,000 orig. miles.In the words of my son "it's big but kinda cool".Even

though it's in great shape we are almost done with a body off resto.But like

any old car it's not without it's problems,someone years ago cutting a hole in the dash to install a push button for an after market windshield washer, man what a killer.Which brings me back to #2.The bottom of the air filter has been

notched(done very well) to make clearance for the fuel line going into the carb.Before noticing this we ordered a carb for a 63 394 (4GC I believe)and was sent the same model that was on the car which now we know was a repacement.Looking at the service

manual the old carb looks smaller maybe this explains it and if thats the way

it is because the new carb is bigger thats OK it's the uncertainty that drives

you crazy.

[rocketraider]

Any early 60s GM boat has high cool factor, esp a hardtop. True, not as desirable as a Starfire, but not as pricey to restore either without all that exclusive trim and leather.

I'm not following you too well on this carb and aircleaner thing. Oldsmobile, unlike Buick/Pontiac/Chevy, used Rochester carburetion exclusively. A SkyRocket would have had a 4GC with a top center front fuel inlet and a steel fuel line from pump to carb. 1963 uses a glass bowl fuel filter mounted on the fuel pump itself. Has someone maybe put a 1962-earlier style fuel filter on, where the fuel filter bowl and return line is right up at the carb? Is it possible it has a 66-later baseplate for a QuadraJet equipped car where the carb opening is bigger? To my knowledge all 4GC from 1952-65 are the same size.

If this car will be done by next summer, may I suggest a trip to the 2003 Oldsmobile National Meet in Cincinnati?

[rocketraider]

Oldsmaniac- where did you find this swaging tool? Would any refrigeration supply company have it?

[Guest]

The swaging tool is a common tool for refrigeration guys...Old styles were nothing more than an assortment of punch like pieces of metal that were inserted in the end of soft tubing [usually copper]. The tubing was held in a flaring block and ya hammered the tool down till ya had expanded the tubing. Then ya simply removed the tool...This expands the tubing a half size bigger. It did this so you could slide a piece of the original size tube inside for soldering...With this no fitting was. The newer style will come in the deluxe flaring kit. Instead of hammering, the swaging head is screwed on where the flaring head would be. You screw the thing down as if flaring but instead you are expanding the tube...Of course the tubing would have to stick out further than if you were flaring....Most HVAC parts and tool supply places will sell this kit...