[squidtone]

Hey guys,
I just bought a set of Edelbrock quadrajet rods #1941 for my late '70's Quadrajet.

I measure the widest part of the taper at 0.048" but the tips are 0.035". Aren't they supposed to be 0.026" at the tips?

The package is Edelbrock, marked with PN 1941, and it was unmolested until I opened it. There are stamps on each rod: "48" "V".

Are these wrong?

[70pontiaction]

Try this page:

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

Good luck!

[squidtone]

Hmmmm.
Upon closer inspection, the stamp on each rod is not "V", it's "M". (the legs of the "M" didn't stamp too well on the curved surface).

And I've searched around and found that "M" rods are truck rods, with a FAT power tip of 0.036".

So I guess Edelbrock put in the wrong rods into the package. Dangit.

Funny thing is Edlebrock does not list a 0.048" "M" rod on their website...so I wonder how the heck this happened.

[Kenth]

Originally Posted by 70pontiaction

Try this page:

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

Good luck!

They´ve got it wrong.
The power tip is at the thin end of rod.

[Kenth]

Dave, can´t see anything wrong?

The 48M rods are Edelbrock #1941.

http://www.edelbrock.com/automotive/...ss-q-jet.shtml

And, all M suffix rods have .036" power tips and are aimed for M4M Truck Q-jets with single main air bleeds located in airhorn, but can be used in passenger M4M Q-jets with proper main jet size.

[squidtone]

Thanks Kenth. I assumed the primary rods offered by Edelbrock were passenger car style rods with the smaller 0.026" "power tip". I didn't know "M4M" meant "M" (truck) rods.
Is it regular practice to convert the primary rod/jet set to the larger 0.036" power tip size when you want to start tuning?

I have a '79 Quadrajet with 73 jets and 55P rods. The car (YS motor) runs lean at cruise, but seems fine at WOT, and I thought I'd just try some smaller rods.

I cannot find 0.048" rods with 0.026" power tips.

I'll keep researching.
Thanks!
dave

[Kenth]

Dave, here is a recipe i´ve found work well with the late 70´s Olds M4M Q-jets on a near std high compression GTO engine:

Carb #17059253
jets .073
prim.rods 55P
idle channels .051
idle tubes .038
upper idle air .069
lower idle air .069
idle air bypass .079
idle discharge .089
main air horn .070
main air body .029
main air nozzle .054
sec rod / hanger CV / H
sec acc. / pri. acc. .052 / .025
sec air tube / sec. well fill .035 / .038
idle screws 3,5
sec air valve/APT 1.38" / 4,5

[Cliff R]

55P rods are not full taper, they have .010" taper on the upper section, so the adjustment range is from .055" down to .045", then they "step" down to .026" tips.

We sell 44 metering rods for the later APT carburetors that taper from .044" all the way down to .026" on the tips. I've used thousands of them in the later carburetors without issues.

To my knowledge Edelbrock doesn't offer .026" tip rods for the later carburetors, on the longer rods for the early style......Cliff

[squidtone]

Thanks kenth. I will dig up my notes on what mods i did to this carb. I built it two years ago but was too lazy to really dig into tuning last year. I hope to in the next month or so and see how my carb compares to your recommeded calibration. Thanks

[squidtone]

oops, missed your response Cliff. Thanks. That's good to know there's a rod option.
I actually built the carb to a recipe in your book (a mild recipe), but the carb runs lean according to the tip in procedure at 2000rpm. I turned the APT out but it still tested lean, and the car runs HOT (although not boilover yet) at idle AND at highway speeds. (I am very confident my cooling system is good, so I suspect the lean condition causes this running hot symptom, but I don't know if a lean condition can cause overheating to that extent)
So that's why I thought I'd try some Jet/rod combo changes and I got some edelbrock parts.
I don't mean to dribble out details like this but I didn't mean for the thread to go this far because I still don't have all my testing/specs straight. But thanks for helping so far guys....

[Kenth]

With the .029" bowl main airbleeds in these units i have found no reason to replace the 55P rods.