deadeyejedi

Ive been learning on theses quadrajets for a while now and starting to figure them out . I do have a question though .Is there any way to figure out the letter codes?I have quadrajets with letter codes (nf,asc,ahf,apw,rj,and a 1972 carb with no letter code at all) Is having a build sheet with these letter codes on it the way you figure out a matching numbers carb and what size motor it came on?How else would you determine the exact factory primary and secondary rods jets hangers etc.?

pav8427

Rods and jets are based on carb number.
Letter codes are a application specific I believe.
In most cases guys with that info will help decode but wont let a list out.
Basicaly to keep the 'restampers' from faking the more rare/high dollar units.

deadeyejedi

This is where I get confused if I have a carb with the number 17056259-1676 asc for example how would one determine what rods and jets are factory ? And how do I know it’s for a 350 or 455?

Fun71

There is documentation for carb number applications, with primary jet, primary rod, secondary rod, and secondary hanger numbers. I have all that in a document that I grabbed off the internet many years ago.

deadeyejedi

I thought there would be but I’ll damned if I can find it still looking though.

Fun71

I’d send it to you but I’m sitting in an airport terminal now and won’t be back near my computer for a week.

deadeyejedi

That’s fine Ken I’ll get to the bottom of it sooner or later . Safe travels

70W-32

17056259 is the "part" number, which is application specific(259) is the application, the 5th digit is the year(76) On carbs with 7 digit part numbers, the 4th digit is the year
1676 is the date of manufacture. 167 is the 167th day of the year(June 15th or 16th. The 6 at the end indicates year
asc is supposed to indicate where the carb was originally assembled. I do not know those breakdowns

The internal parts for jetting will be related to the part number

pav8427

Pics are from the AC Delco carb bible.
A part number search for rids and jets should get you there.

deadeyejedi

on the 259 I was led to believe the 2 means federal emissions the 5 was Oldsmobile division and the 9 being an odd number would signify a manual trans (but the last number odd or even doesn’t always hold true to determine auto or manual trans )

442Harv

My book says,fits 1976, 350 A body, with 2.41 axle and AC. Prim jet.067, rod,.041, secd jet,0.135,rod,.053, rod code CV

70W-32

Ive seen that explanation also, but it doesnt hold true. On earlier carbs(7 Digit part numbers, like 7040258), the 3rd number denoted Oldsmobile, 4th was year, and last 3 defined use. in this case 70 W30 auto. 7040257 would be 442 Auto, and 7040256 was W30 4 speed. So the odd/even thing doesnt match up.
Ive realized that some online explanations relate to other makes(Chevy), but dont relate to all GM makes

deadeyejedi

Thank you Harv that is exactly what I was looking for that carb I’m working in now has what you have listed here so I now know that is what it came with and can go from there from a tuning standpoint point . I wish I had that book it would come in handy for these other carbs I got .

deadeyejedi

it’s interesting that my factory 455 quadrajet only is up one jets size same rods and same secondary hanger not positive about the secondary rods though it has cj’s in it .

joe_padavano

You need one of these (there was one on ebay last week for $25):






Inside, you'll find pages like this. Note that the 10756259 was used on 1976 350s in Cutlass A/C applications with Federal emissions.

deadeyejedi

I definitely do and I’m on the hunt now thanks for posting

deadeyejedi

while on the subject of these quadrajets ,last night while working on my run stand motor i refired it only to find the carb was severely flooding( 70 olds 350 carb).This carb ran and worked great last year on this motor. I removed the top and found a spider caught up in the seat.i also noticed it had no needle jet retainer wire .I didnt know until after some research some guys omit the retainer wire and just let the needle and seat do its thing! i did have a spare and put one on it .ill see how it goes tonight

pav8427

I have only found that that retaining clip is actually another tuning point.
If using one, tweak it so the needle moves as soon as the float moves without holding needle open.