VIN indicates the car was originally a 2BBL carb. so this intake was added by a prior owner.

What are these tubes in the primaries?

Also, the intake plenum appears to have been coated with a black ceramic or powder coat?

Casting # 22503087 GM PatsWiki shows 1980 307c.i.

 

Not a 72 intake, as it has a egr valve Tim

 

Yes, that is the common early iron, regular sized port Olds 307 intake. Yes, those are part of the EGR system.

 

Casting 22503087 was used on the 1980-84 307 motors and on 1980 350 motors.

 

It's going to stay on the engine. My curiosity was aroused during a carb change. The Sean Murphy Q-jet has never worked well. Hello Holley.

 

Whatever carb you use buy a wideband O2 and tune it right.

 

Which wideband 02 do you recommend for the '70 442 hobbiest?

 

I'm crushed. In addition to the 307 intake; the block casting of 3161-5A indicates its a 307 mouse motor.

Should I apply 4-4-2 badges on it to gain some self respect?

Seriously though - it's not a bad performer. Not much different than the 350 that was in my original Cutlass back in 72.

 

I would go for stripes on the trunk...

 

Don't stop short - a wing is essential.

 

I'll trade my Q-jet for your wing

 

The early 307 was an Ok motor for power and very reliable. Only a 17 hp and 30 ft more for the low compression 350's with single exhaust. Add dual exhaust to the 307 will bring it on par, more or less. What motor was the Shawn Murphy Qjet tuned for? Cutlassefi sold me a AEM wideband, very nice. My Qjet was very rich, a few minutes of tweaking, got it bang on. If you set up a Qjet right when rebuilding it, it is very easy to tune.

 

I bought the Q-jet from a member here and sent it to Sean Murphy Inc for complete rebuild. Analysis by Murphy indicated it was for a 76 vintage and re-tuned for a 72 350 which at the time I thought I had.

1. It was always hard to start after sitting for a few days but ran okay after it started.
2. It never really engaged the secondaries to the point that you heard the typical Q-jet roar.
3. Recently when idling for 3 minutes during A/C charging it loaded up rich and fuel overflowed through the accelerator pump plunger.

I had a local guy with a good reputation for tuning carbs spend some time with it a while back but no improvement.

 

I'm sorry, but I don't understand the horror stories from people about carb tuning. Your description says that the carb wasn't built or adjusted correctly. None of that is difficult to resolve. I have no idea who "Sean Murphy Inc" is, but apparently they don't know how to built a Qjet correctly. And no "analysis" is required to determine the origins of a Qjet. All you need to do is look at the stamped number on the side.

 

Sean Murphy used to work for Jet, recalibrating their Qjets. He has a good reputation. That 76 carb is one of the best to rebuild for performance being 800 cfm once the idle calibration is enriched. Not an issue in your case. It is also very tunable, easily adjusted choke, pull off, idle mixture and APT. I always notch the APT adjustment and tap the air horn for a 1/4" plug. It makes adjustments very simple for part throttle tuning. It sounds like a needle and seat issue and possibly the float level as well.

 

Sean Murphy Induction

 

Joe,
I yewsta dive right in on anything and figger out a way ta make it werk. I guess I've grown tired of fixin.