CR-SuperChevy

4bbl Q-jet i know it has a K hanger i dont know what the rods are but im swapping in a B hanger with CC or CK rods i have the specs here..

CC 1347/0* 1236/20* 1129/40* 1024/60* 599/70* 300/80* 300/90*TipL: M

CK 1345/0* 1291/20* 1154/40* 927/60* 527/70* 527/80* 527/90* TipL: L

what do those numbers mean ? i can make guesses but yeah im assuming that CC rods would give you a better power tip at WOT than CK rods would because of where the power tip starts? which would be best with my setup thanks guys,

kevin

five7kid

iTrader: (14)

The "L" and "M" refer to the power tip length - "long" and "medium", respectively.

The other dimensions are the diameter at the particular degrees of AV opening. Since the CC diameters are smaller soon after the AV starts to move, and has a longer power tip, it would be the richer rod of the two.

curt86iroc

for your car i would go with CC's like five7 said. CK's are good for my car because of the light mods, but once the cam and heads go on ill have to upgrade.....

CR-SuperChevy

CC's it is guys thanks alot!!!

five7kid

iTrader: (14)

Well, that's not exactly what I said. I simply said the CC's would be richer, not that they should be used.

When I had a q-jet on the 396, CK's slowed me down compared to DR's. That may be due to the altitude here, but richer isn't automatically better.

It's a matter of tuning, and if you need something richer than the CK's, then CC's are. However, if the CK's are right or too rich themselves, then the CC's aren't the right thing to do.

CR-SuperChevy

haha ok so now it gets complex... well with my cam heads and headers going on i think cc rods would be the right choice ive also modded my carb up to 700cfm by removing that tab and set the AV to 0 tension im getting a one inch 4 hole carb spacer. my cam actually blew up couple weeks back one of the front lobes just ground down to nothing its a circle its horrible so i sent it into comp cams to have it warrentied so i took my car off until january so i decided to rebuild my engine (top end) but im debating pulling it because of the metal shaving from the cam getting down in the bottom end and just breaking stuff so i dont quite know what im going to do any sudjestions?

kevin

Damon

You will never be far from optimal with a set of DR secondary rods on either a B or G hanger. They are not as rich at full opening but that's not where the secondary side of the QJet has a problem. It's when the air valve is just starting to open- the first 30-40* of air valve opening where almost all of them are too lean. A set of DRs will be significantly richer in this transitional area and will give a noticable increase in throttle response and mid-RPM torque vs. most other sets of rods.

CR-SuperChevy

im completely lost in all of this

five7kid

iTrader: (14)

The amount the rods are pulled out of the secondary jets is proportional to the amount the AV has opened. It doesn't just flop open, it opens more as air flow (RPM's) increases. Since the amount of fuel that is let in is dependant upon how much of the jets the rods are blocking, thinner rod at any given point means richer mixture.

The quicker the rod tapers down, the richer it will be quicker. That's the big advantage of the DR rods.

Of course, the hanger gets involved too, since a lower letter hanger (such as "B") holds the rods farther up at any given AV position than a higher letter hanger (such as an "N").

And, AV opening rate is controlled by varying AV spring tension, but that doesn't affect mixture ratio as much, rather just how much the carb will be allowed to flow (to avoid bog).

As you start playing with it, it all starts making more sense.

flyway190

What I do is run DR's on the street and swap CC's in at the track. The CC's may be rich, but my car is noticeably faster with them at WOT.

CR-SuperChevy

Ok well sounds good thanks for all of your help ill post back with what i do and how it goes thanks

CaysE

How about a stock carb rebuild on a 305? I'd like to put new hangars and rods in it, so should I go for DRs on a B hangar? Like I said, most everything is stock; I just want a little more out of this setup. Nothing drastic.

[edit] the car is in the sig, but the carb is actually from an 84 LG4 Camaro SC.