Olds64

Hello. I am in the process of rebuilding my Olds 455. I need some help deciding which Quadrajet I should rebuild and use. I currently own two Quadrajets. I was hoping someone could give me some information on the differences between the two.

The first Quadrajet came with the 455. It should be a Quadrajet that came on the 1973 Olds 98 with J heads. I identified a number on the back of the fuel bowl (7046222) I looked for a number near the accelerator pump but couldn't find one.

I believe the second Quadrajet is newer. It has a casting number next to the accelerator pump (17064839). It also has the following code on the fuel bowl next to the linkage.

17082224
1462 FJP

Which carburetor should I rebuild and use with my 455? Does either one of these Quadrajets have desirable metering rods or jets?

J-(Chicago)

The first one is a 73 olds carb

The second is from an 82 chevy I think.
Most likely, they both are undesireable.

dar83501

Unfortunetly, I know nothing of Quadraflushes...

J-(Chicago)

Well then here's a quick lesson.
The number that you want is on the driver's side going vertically.
In Olds 64's case the number is
17082224
1462 FJP

170 is the number for rochester
before 1976 it is just 70

82 is the production year

the next #2 means non california emissions. If it was a 1 I think it would be a Cali smog carb

the NEXT #2 indicates the division.
0,1,2 = Chevrolet
3 = Cadilllac
4 = Buick
5 = Oldsmobile
6,7 = Pontiac
8 =Mercruiser Marine?

The 4 indicates manual or auto trans. Evens are usually automatic, odds are manual

1462 is the date of production. In this case: The 146th day of 1982

FJP is the letter code for the manufacturing plant.

This is enough information to identify a carb, HOWEVER it is also enough information to misidentify one as well.

Olds64

J, thanks for the tips. Both of those decodes sound about right. I knew the older carb was from a mid to late 70s Olds engine, and I knew the other one was from an 80s Chevy. BTW, you mentioned that both aren't particularly desireable. Why is that? Is there a specific Quadrajet that is more desireable than others? Thanks.

J-(Chicago)

They're all nice carbs, but some of the 1975 carbs were 800 cfm Which in my opinion bigger is better. The 800s have lot of potential, and if you don't particularly need 800 you can always use different jets to tame it down a bit.

J-(Chicago)

I am an admitted newbie at carburetors however, so take what I say with a bag of ice cream salt. Danny S would be a better person to chat it up with about this subject.

Oldsguy

I know a guy that would trade you some C heads for one of them. Give me a call sometime.

88 coupe

Not true, in this case. Q-Jet only supplies what the engine needs, at a given time.

Per my previous statement: Everything else being equal, both carbs should use the same jetting.

To answer the original question. I would flip a coin.

Norm

Olds64

Hmm... well I will probably use the carburetor off of the 70s Olds engine. The one off of the Chevy has a 90* bend where the fuel filter and inlet are. In addition, I already gave SOMEBODY the kickdown mechanism for the TH 400 off of the Chevy carburetor.

I purchased the Rochester Carburetors book by Doug Roe for this rebuild. I have rebuilt plenty of Quadrajets before but I figured I could always find a few pointers and high tech tips. I will have to ask some more questions once I start to rebuild it.

Maybe this evening I should go buy a rebuild kit...

Olds64

Ok, I bought a rebuild kit tonight along with some Berryman's carburetor cleaner. However, I was wondering if anyone knew of a place where I could get a throttle plate bushing kit a little cheaper than the one below? I guess the kit is a little pricey because it includes 16 bushings. I don't need that many for one carburetor.

http://store.summitracing.com/partde...5&autoview=sku

abody

i just had my 1970 rochester cleaned,rebuilt and tuned for $214 bucks, he took it off and put it back on for that price, if i would have taken it off it would have been $140, palacio carb in phila.

Oldsguy

And it was broke to boot! Ooops, guess I just let the cat out of the bag

Olds64

Yeah, I know I can get my carburetor rebuilt professionaly for a reasonable price. However, I am not rebuilding it myself to save money. I would like to rebuild it just to get the satisfaction of doing it. Like I said, I have rebuilt plenty of Quadrajets with decent success. I have never redone the throttle plate bushings though. I hope someone has a good lead on another kit for me.

Oldsguy

Jesse, do a search over at ROP. I think I remember somenone mentioning or referring to a guy that sells bushings and shafts that you can "do it yourself". You know my memory, I hope that is where I saw it. If I can remember better I'll let you know.

Olds64

Ok. I disassembled the carburetor today and found a surprise. One of the primary metering rods is broken!

The rods have 53C stamped on them and the primary jets have 70 stamped on them.

I guess I have two options. I can tear apart my other Quadrajet and salvage the primary metering rods and jets, or I can order new ones. I already checked and it would only be $20 for new metering rods and jets from Summit (in various sizes). What should I do? Are there specific primary jets and metering rods that I should buy? Any information would be appreciated.

J-(Chicago)

Yeah, I'd just pick up some new ones. They should all be readily available and easily looked up.
If yours is pre 1976, You can't use the ones from the Chevy carb

The "70" carbs have longer rods than the "170" carbs.

J-(Chicago)

http://www.carburetion.com/rodshang.asp

What is the number going vertically on the olds carb? I don't think you gave us the full number yet. Just the fuel bowl.

If it is also a "170" carb you may be able to use the chevy carb rods.

Olds64

I tried to disassemble the Chevy carburetor. Unfortunately it was so tarnished and worn that I couldn't get the float, needle, and primary metering rod assembly out of the fuel bowl. I would have to do some heavy duty chipping away at the bird's nest / oxidation / wasp's nest.

Anyways, I think I will just go ahead and order new primary metering rods and primary jets. That would be the best bet since they are so cheap.

BTW, I cleaned the fuel bowl on the Olds carburetor and found the following number.

7043251 RB
0193

J-(Chicago)

ahh that's the number I was looking for.
That makes it a 73 olds carb, non smog 4bbl, from a car with a manual transmission. Not a 75 or 76.

Made on Jan 19th of 1973

Olds64

Ok. I did some reading and the primary metering rods I have are triple taper with a .053" diameter (53C). In addition, the primary jets are .070" in diamater (70). Finally, my secondary metering rods are stamped with CH, and the hanger is stamped with H.

Can I replace my primary metering rods with these rods available from Summit?

http://store.summitracing.com/partde...5&autoview=sku

These rods are .052" in diameter and I assume they only have a double taper (I read that Oldsmobile was the only one to use triple taper rods). I just want to make sure these aftermarket rods work correctly with the jets in my carburetor. Right now I don't plan on changing the secondary metering rods or the primary jets unless someone knows of a good combination to use on a street driven engine which is mildly built.

I appreciate all of the help.

J-(Chicago)

How 1970 triple taper rods got into your 73 carb is anyone's guess. Looks like you have yourself a frankenstein carb there
Do you want the ''correct'' ones for your carb?




-----------------------------------------------------------------------------
The Doug Roe book on Rochesters, in the chart showing all the primary metering rods, shows the only triple taper rods ever made were rods 7040699- 48C and 7040701- 52C, and these were used on 1970 Oldsmobiles only. Olds was also the only one to use the triple rods.

The triple taper rod was and attempt to fine-tune the fuel curve more precisely than the dual-taper rods, introduced in 1968, allowed. I guess it didn't work well enough to justify the expense, since they went back to dual-taper rods the very next year. It seems that the carb section of the Olds engineering department was getting a lot of overtime calibrating the 1970 units, what with the triple-taper rods and the no-rod "W" units. Apparently, not everybody went to the dual-taper rods in 1968, however.

J-(Chicago)

I think this would be correct for your carb. (#'s from an AC-Delco manual)
1973 455 carb 225 HP

Main jet 7031969

Primary rod 7034850- "50B"

Secondary rod 7045779- "CH"

I'm clueless on the secondary hanger

Olds64

J, thanks for the info. I have the Doug Roe book as well and I wasn't able to find the 53C primary metering rods listed so I assumed they were triple taper. Regardless, I will have to get some new ones since one of the originals is damaged. Thanks for the original specs. At least that gives me a way to get my Frankenstein carburetor back to normal.

J-(Chicago)

The 50B's are available here for 12 bucks
http://www.carburetion.com/rodshang.asp

J-(Chicago)

Let me know how it goes for you. I have 5 or 6 carbs just hanging out if you need another.

Olds64

Check it out! I purchased two 73 primary jets and two CV secondary metering rods from the local carburetor shop. The 73s were right in between 72s and 74s that Bob G. suggested in his Oldsmobile Engine Tuning and Modification guide. Bob G. also suggested the CVs as one of about 10 secondary metering rods that are good for mild street cars (not too rich at WOT but better than the CHs that I had). I think I am going to take Bob's advice again and install stock primary metering rods (the 50Bs).

J-(Chicago)

Good idea. I have that tuning guide laying around somewhere too. It's a pretty nice little book. I have to do my carb again when the weather warms up. Right now my secondaries are frankensteined together from 2 different needles that were in the drawer haha. 1 is from an 80 lesabre and one is from an 87 Monte SS. I paired them together wrong when I put them away, and their other halves are amongst crap in the garage somewhere. Oh well, they'll get me through winter just fine.
My 4 extra carbs are not "170" carbs, as Murphy's law so dictates.