Would i have to change the metering rods in a carb that came off of a 307 to work properly on a 350?

 

depends on what year 307 and what year 350. any modifications/performance changes over stock engine? etc.

this link is a good reference to tune any q-jet.

http://www.route66hotrodhigh.com/PowerTuneQjet.html

 

Is it a conventional Qjet or a CCC carb?

In any case, you need to change more than just the rods. The secondary air valves on the 307 carbs are limited to only about 70 degrees of opening angle to limit airflow to the smaller motor. You need to file the stop to get a full 90 degrees. You definitely want to change the secondary metering rods. If this is a CCC carb, you can't change the primaries - you have to burn a new PROM.

 

what does "burn a new PROM" mean?

 

307s came with the CCC system - the computer controlled Qjet. The primary side fuel map and ignition curve are controlled by the computer (ECU) and are stored on a Programmable Read-Only Memory chip (PROM). Changing the fuel map requires reprogramming the PROM, called "burning" a new PROM.

Again, since you didn't answer the question the first time, is this "307" carb a CCC carb or a conventional carb?

 

oh snap, its a CCC!

 

You can and should at least change the secondary rods (easiest) the 307 has the leanest thickest secondary rod ever used (DD) and after un-restricting the secondary which can also be done with needle nose pliers. Swap the secondary rods (all years swap) you have that are thinner , something around .410 - .567 tip diameter is not bad , flip your lid and go

http://www.hioutput.com/tech/qjetrod.html

 

If the OP wasn't even sure the carb was CCC until now, the NEXT question is, do you plan to run the car on the computer? If not, they step away from the carb and get a different one.

 

I plan on running on the computer. My goal is to have a mild built 350 to put in my daily driver without all the emission stuff that came on my 307.

 

Joey, please

 

I got this one.

So WHY would you want to keep it on the CCC system? The ignition timing curve cannot be altered without burning a new PROM. Yes, you MUST retain the CCC distributor for the CCC system to work. The primary fuel map canot be altered without burning a new PROM. In both cases, the stock PROM is mapped to satisfy emissions requirements of your 307. In particular, the fuel and spar maps assume the EGR valve is functioning, so they run extra lean in the midrange with aggressive advance. This causes pinging if the EGR is not functioning and is definitely too lean for a 350.

If your installation is "without all the emissions stuff", then the only functions you care about that you'll lose by deleting the CCC are the torque converter lockup and the A/C clutch disable at wide open throttle. I both cases there are simple solutions to allow those functions to operate without the computer.

 

Did not know that. So what are the solutions for the torque converter lock up and a/c clutch? I think i read somewhere that without the lockup, you cant drive in overdrive. I THINK i read that.

 

You didn't read that.

You really need to educate yourself before making these decisions.

The converter lockup and OD are unrelated. OD is engaged hydraulically in the valve body. Converter lockup is actuated electronically with a solenoid valve. Many vendors sell aftermarket kits to actuate the lockup without the computer.

The A/C clutch disable simply requires a switch on the accelerator (like the old TH400 kickdown switch) to cut power to the clutch at W.O.T. Or, do nothing and there will be an undetectable additional drag on the engine at W.O.T. due to the compressor.

 

i suspect education is half the reason for a forum. At least, thats half my purpose. That and to look at others cars.
Sobi have learned something today. I ask these questions because im planning a rebuild for my 85 delta. So before i actually do something foolish, i ask all the questions i have. Thanks for the education!

 

It's good that you are asking questions, and we are happy to help, but getting the info from you that we need to provide a complete, correct, and useful answer has been like pulling teeth. You would have gotten a better answer much faster (and frankly, with less frustration) had you told us what car, what engine, and what you planned to do with it right in your first post. We still can't read minds. For example, the answer you got in the second post is relatively worthless to you because it doesn't apply to the CCC carbs. Now, if you plan to ditch the computer and use a conventional Qjet, then it would be very useful.

Also, you REALLY should obtain and read a Chassis Service Manual for your car.

 

Now that i know a little more, i do plan on getting rid of the computer. And i have a chassis service manual for my car. Been studying it for a good week now. And now more questions arise. And i hope you, joe, chime in! Im gonna need every bit of help during this build. Its my first one!

 

So if i remove the computer, i would need a switch for torque converter lockup and the A/c clutch Correct?

 

Yes for the TCC.

The A/C clutch will work just fine without the computer. It will NOT disengage at W.O.T., however. As I pointed out above, you may not care about this. If you do, then yes you need a NORMALLY CLOSED switch that opens at W.O.T.

 

Another question, what year and model? What has been done to the 350? A stock smog 350 would run OK, even on a stock 85- up swirl port 307 tune. A 350 with any sizeable compression or cam increase will run terrible on the same tune. The early 80's non swirl port motors run slightly less timing and Hurst/Olds and 442 carbs have richer calibrations but still won't be ideal.

 

The question was just to see what i would need for a future rebuild. Im currently looking for a 350 and a qjet to rebuild and put in my 85 delta 88. Im going for a daily driver but with a little power. A mild build. And matched with a 200r4. Im hoping to get that built to handle a decent amount of torque.

 

Cool! I appreciate the help man

 

your only a hour away from me. I am selling a 403 79 TA long block cheap and also a 68 350 short block . The 403 would be great in the 85 Delta n place of the 307 . It is STD engine that turns over supposed to be 80k miles. Just needs proper vat clean/ prep and re ring bearing as far as I know.