This is an open ended question with a finite number of answers. I have had the 350 engine rebuilt in my 71' Cutlass to original specs with the exception of a "mild" cam upgrade. The QJ carburetor had sat for 9 years and even though the car would start right off each morning, I decided to rebuild it. I did rebuild it with a really cheap kit with mainly gaskets. It works fine, BUT, I would like to modify it to take advantage of the cam upgrade.
I contacted "the guru "Cliff" providing every detail of the finished product, but did not hear back AFTER I said I was a watchmaker and preferred to do the work myself. So the question is, what would make sense for jets, and metering rods? Should I make my own rods as I'm experienced in making parts way more intricate than metering rods. It's not about the money, it's about achieving maximization of a given equation.
Yes, most new cars can easily smoke my old 71', but so many of those cars will be in the graveyard well before my 71'. The sound of an old V-8 cannot be duplicated and that is a very wonderful part of owning a nostalgic vehicle. Just looking for suggestions and all are appreciated.

 

My guess is that Cliff doesn't mind consulting, but doesn't want to give the info away. I would suggest buying his book and follow it. I intend to do that when I get to the point of needing a properly tuned carb.

 

First question is, what is your Quadrajet code number?

Also need better engine build and driving desire.
We do custom builds, and we also have all parts for Quadrajets. Most of our business is performance or race applications, so we do understand what is needed.

For a base line, with limited information, here are some ideas.
Jets 70
Primary rods 44B
Light power piston spring
Smaller secondary rods. Original would be CG
Main air bleeds and idle air bleeds are probably fine.
Idle tubes should be .038
Down channel restrictions .054
Increase idle screw hole to .090
Replace secondary air valve cam and tension spring. Set spring to 3/4 turn
There are several other things that can be done, but wanted to toss out a starting point for you.

Be glad to help and please consider us for parts too!

 

Well that is disappointing to hear.

The 71-72 engines were advertised as 8.5:1 compression from the factory (but really were ~8.1:1) and using "factory replacement" 24cc dish cast pistons that are short on compression height and then using thicker Fel Pro composition head gaskets during a rebuild results in ~7.6:1 compression ratio. You could have easily bumped it up into the 9:1 range during the rebuild with better pistons to gain more power and still be very driveable.

So what cam did you use? With such low compression it is really easy to overcam the engine.

FYI, my carb has all the factory innards and it works well with the engine with the upgrades shown in my signature line.

 

I have no complaints with the current setup, I just want to explore a few different combinations for curiosity's sake. I'll look you up and order some parts. Thank you.

 

I thought about the above mentioned and decided to go back with the original stuff as the car is original. Regardless, I think I missed on that one. I put in a better cam and do like it's addition. The cam is 204-214 @50 with a 112 centerline. It's a good match so far. I just like tinkering with the carb. as I find it entertaining. When I get the paint job done, it will be finished. The paint now is quite good, but not perfect. It's a car I'll drive maybe 500 miles a year.

 

A 204º cam is a perfect upgrade for the factory cam and should be OK for building cylinder pressure with the low static compression ratio.

 

The Edelbrock 204/214 cam does lower cranking compression some, my 8 to 1 very good condition 350 had 140 to 142 psi. You may gain slightly from the carb modification, worth a shot. Check your throttle shafts for wear when you have it apart. Add dual exhaust as well, makes a nice difference and sounds better. There is no sound like an Olds V8.

 

My notes show that carb would have 69 jets and 50 primary rods. Most Oldsmobile Quadrajets were set up very lean like this. Going to jets/rods I mentioned seem to wake it up a bit, based on past experience and input.

 

The data I have and my original 350 carb (7041250) have 70 jets and 49B rods on the primary side and AS rods on the secondaries.

 

First and foremost, thank you all for the input. My expertise in cars is the audio portion. That I can do blindfolded. While having the engine out I decided to add dual flow master exhaust and am glad I did. The cranking pressure is 152 with the cam installed. Vacuum is 18. Here is the kicker. In 1973 when taken in for service work, Oldsmobile replaced the original QJ with what is still on it today, a 7043250. They didn't charge for the swap because they could never get the original one to perform for any extended amount of time. We've rebuilt it maybe 3 times over the years. I think the 73' has a larger fuel inlet? Non the less, it's been trouble free forever.
I rolled over my magic 8 ball and came to the conclusion that the secondaries could use more fuel than is available currently. By the way it still has points and drum brakes. I have other cars which are superior in all areas except they are not a classic Oldsmobile and they do not compare for the fun factor. My only complaint is the car that people used to say was "old, get a new one", draws attention even going 80mph down the road. Thank goodness so far none have had red lights on top.

 

Another audio guy! Good to have you. I was a mobile electronics installer many years ago. Was your experience more recent?

 

We actually won the first IASCA show in 87. I got out of car audio after that and stuck with the home end for 20 years. We used Zapco 3 piece amplifiers mainly. Lots of fun times.

 

Ha! I also lived through the constant "stop messing with that old car and get a new one" from friends and family back in the 80s.

 

I remember those Zapco amp and EQ systems. They were unnecessarily complicated for the time. At that time I was working with the same type of equipment, even took a few cars to the first Car Audio Nationals. Did that gig for 15 years. It was a blast but it is a young man's game.