New replacement Carb for Olds 394 V8.

Moin · November 19th, 2004

I'd like to know if there are any aftermarket new replacement 4V Carbs I could purchase for my '63 Olds 98's 394 V8? Right now it still has its original Rochester 4bbl carb which I'm having rebuilt, but if there are any nice new replacements available out there which are direct bolt on replacements with no major modifications required, I wouldn't mind getting one.

I checked the Summit catalogue and found the Rochester Quadrajet 750 cfm Stage 1 Carb for $349.95. Stage 1 is for stock factory performance. Would this fit my application? Then they have various Edelbrok and Holley, but I don't particularly care for Holley's as I heard they require constant tuning.

someChevelleguy · November 19th, 2004

I'm not 100% certain of this, but I heard that Edelbrock is discontinuing their Q-jet. There was supposedly some licence issue, or something something to do with dwindling demand vs. retooling costs.
I would say that a Q-jet is a pretty versatile carb, relatively simple, potentially economical but tricky to fine tune unless you get an expert who really understands them.
Forgive my ignorance, but does the 394 carb mounting fit a spread bore carb? If so, then I would hazard a guess the the Q-jet is a good choice. It is worth the effort to find an expert to dial everything in on it, as fuel economy and performance depend on things happening under the right throttle settings (if that makes sence).
There's my 2 cents worth.

JLS2009 · August 16th, 2009

The Olds carried a Rochester 4GC. I have a show restored one I would consider selling.If you interested contact me laman1955@yahoo.com the qjet will not work unless you use an adaptor which would raise the height of the carb and possible hood clearance problem which you dont want.

carbking · August 16th, 2009

Question 1: no, there are NO currently available new units that will work without MAJOR modification on your vehicle.

Question 2: no, the quadrajet is a spreadbore, and your Olds uses a squarebore, thus the Q-Jet will not fit. Plus the one you mentioned would require MAJOR modifications even if you change the intake manifold.

Jon.

joe_padavano · August 17th, 2009

Quote:

Originally Posted by carbking

Question 1: no, there are NO currently available new units that will work without MAJOR modification on your vehicle.

The definition of "major" is relative. The Edelbrock AFB clones will work, but fabrication will be required to connect the kickdown rod for the hydramatic. Of course, the jetting will need to be tailored to your car.

carbking · August 18th, 2009

Quote:

Originally Posted by joe_padavano

The definition of "major" is relative. The Edelbrock AFB clones will work, but fabrication will be required to connect the kickdown rod for the hydramatic. Of course, the jetting will need to be tailored to your car.

The definition of "work" is also relative.

The clones are calibrated for a small block Chevy.

The Olds has a "slightly" different fuel requirement. For best results, one would need to change the primary jets, secondary jets, primary venturi cluster, secondary venturi cluster, metering rods, vacuum piston springs, and auxiliary airvalve!

If one has a vehicle old enough to have running boards, one can get the engine to "work" by hiring a 15-year old to stand on the running board and pour fuel into the engine out of a leaky boot. Now how well is "works" is a different story!

Jon.

joe_padavano · August 18th, 2009

Quote:

Originally Posted by carbking

The definition of "work" is also relative.

The clones are calibrated for a small block Chevy.

The Olds has a "slightly" different fuel requirement. For best results, one would need to change the primary jets, secondary jets, primary venturi cluster, secondary venturi cluster, metering rods, vacuum piston springs, and auxiliary airvalve!
Jon.

I noted that jetting (jets and rods) need to be changed. I have several of the Carter strip kits for just such tuning. The air valve wrap on the AFB can be adjusted. Changing the venturies is pretty extreme and unlikely to be necessary in my experience.

Everything is relative. Rebuilding the OEM 4GC is certainly one option, and would be my preferred choice. If that is not practical or not desired for whatever reason, an AFB will certainly work. Again, we're talking about degrees of "goodness". Bolt on a stock AFB with the evil Chevy calibration, and the car will certainly start and run, probably acceptably for most people. Tweaking the jetting (using both jets and rods) will optimize both economy and performance. Some of us actually enjoy the process.

talarico8447 · August 18th, 2009

Moin, If your having it rebuilt im sure it will work fine. The 4GC carb is a good one in my book and you wont have fuss or pain of making an aftermarket carb work.

Starfire61 · August 18th, 2009

I hope Moin got his carb issues figured out by now, as his initial post on this thread is almost five years old...

Anyway, I've heard some horror stories about getting the car to shift properly after coupling an aftermarket carb to a Slim-Jim TV rod. I"d never attempt to replace the 4GC on a Slim-Jim equipped car for that reason alone.

Chuck

rocketraider · August 19th, 2009

The key to getting an Edelbrock set up for a Slim Jim on Olds is to look at the linkage on a similar year Pontiac Catalina or Grand Prix, which will have a Carter AFB/ Slim Jim.

'Course our Pontiac brethren have the ability to ditch the Slim Jim altogether and put a Turbo HydraMatic behind their 389s. A good friend has a 64 GP that has had a 200R4 installed. He don't worry about Slim Jim throttle valve adjustments. He sets the TV cable (a simple job) and goes down the road.