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I have a 67 Cutlass Holiday Coupe. Stock 330, low compression and 2 barrel. Dual exhaust. Jetaway tranny and 2:87 open rear end. My intensions with this car is to make it a reliable and fun driver.
I am looking to swap out the 2 barrel carb and manifold to a 4 barrel carb and manifold. I have an Edelbrock Performer (p/n 2711) intake. A month ago I bought a used Edelbrock Performer carb (p/n 1406), that I plan on rebuilding. Out of curiosity, I emailed Edelbrock to see what they recommended for my setup. They told me that I should use their AVS2 (500 cfm) carb with a 1/2" spacer. The more I have read about the AVS2 carbs, I am really liking them - which means I am going to sell the 1406. But I am torn between the 500, as recommended by Edelbrock vs going to the 650 version of the AVS2. From what I have read and watched online, I don't see a lot of info about people upgrading to a 500 cfm 4-barrel, it's usually at least a 600 or larger. I have done the calculations, that you can see online, and it all points to a 500. I am learning on the fly and looking for some input. Thanks!
A properly calibrated Qjet will be a better choice. The Qjet is arguably the most sophisticated 4bbl ever made. The triple venturies in the primaries improve atomization and part throttle response on the street. The large secondaries provide the airflow when you need it. Match the jetting to the factory calibration for a 1967 330. And FYI, the reason why E-brock recommends a spacer is because their own carb won't clear on their own manifold without it.
Yeah, 500 is small for a 330. The spacer is a good idea to prevent heat soak. The AVS2 has quite a few upgrades or the regular 1406. Get a full calibration kit and a wideband is best to tune, otherwise just guessing. It may be way off out of the box. A custom tuned 1976 to 80 800 cfm Qjet is also a good choice.
Yeah, 500 is small for a 330. The spacer is a good idea to prevent heat soak. The AVS2 has quite a few upgrades or the regular 1406. Get a full calibration kit and a wideband is best to tune, otherwise just guessing. It may be way off out of the box. A custom tuned 1976 to 80 800 cfm Qjet is also a good choice.
An aluminum spacer conducts heat. I've never had a "heat soak" problem, and I run E10 pump gas with no issues. Right up there with the well plugs myth. A Qjet calibrated for a 330 is the best choice.
The heat soak issue with AFB/AVS goes back to TSB's from Chrysler in the 60's, when they were factory equipped, it's online somewhere. I meant a phonelic spacer, which will help somewhat. I've had the least to do with the AFB/AVS of the Carter carbs. I ran a Thermoquad, had issues as well as the one on our families 82 Dodge Diplomat police intercepter. The rest of the Carter 1 barrel and BBD 2 barrel carbs are plain junk in my opinion. Just not a Carter fan from running and working on them. My vote is obviously the super tunable Qjet as well.
I did a 4bbl swap on my 67 330. Only did it because I already had everything and the 2bbl was acting up. I used a quadrajet off a 403 and an rpm intake. Ran well, not much of a power improvement though.
Regarding the spacer, here is what the tech from E-brock emailed me:
"We recommend part #8725 spacer for best seal on intake."
And this is off of their site -
"The Edelbrock Carburetor Spacer #8725 divided design is for use with Dual-Plane design intake manifolds. The Edelbrock #8725 divided spacer is 1/2" thick and made of wood fiber laminate. The superior heat insulating properties of wood fiber laminate are ideal for reducing heat transfer to the carb."
I might just rebuild the 1406, for now, and see how the car runs with it before going any farther with this subject. I already have the rebuild kit for it and the calibration kit.
Yeah, the better first gear with help acceleration a bunch.
Absolutely.
Taz you would need to add 100 gross HP to your ride as is, just to match a 3sp auto 69/70 factory 4bbl 350 version. A 2sp 350 hp 1966 442 shares the exact same performance as a 310 hp 350 with a 3sp auto.
I'm not saying the carb/intake swap is a complete waste of time. But just to temper your expectations... It does not benefit a 330 the way it does a 350. The under 4 inch bore and negative 20 cubes are a big player here. 4bbl 330s had better cams than 2bbl versions for a reason.
I've documented this info on here many times. My 42,000 original mile 3sp manual 67 Holiday Coupe got tweaked to the nines over 3 decades. Swapped to Duals, Performer Intake, Holley 4BBL, Full Length Headers, Electric fan, Super T10, etc. But no cam swap or better rear gear. It felt no quicker than day one to me. The crispness it had stock on the street was gone, but did pull harder on the highway...
Thanks, Phil. I appreciate your input (and input from the others that have added to this thread)! It's all great and very educational. Like I said, I'm learning on the fly.
When I get a new to me project, like this car, I tend to get excited (the wife would say overly excited) and want to jump in with both feet right away. LOL When I first bought this car (Jan 2024), I was going to do a 4 wheel disc brake swap, electronic ignition and a Sniper 2 throttle body EFI. I have reigned things quite a bit...I have the points ignition working great, so no electronic ignition. Drums brakes are working as they should so I'm not going to even do a front disc swap. And after doing probably too much reading and watching videos, I went from wanting EFI to a 4 barrel and now the more my education continues, I am leaning towards leaving the 2 barrel on it.
I will table the transmission upgrade for now, but you have planted the seed. LOL
The only comparative data I have is the actual Oldsmobile specs for the 1972 350 engine configurations. While the 1972 350 engines are not the same as the 1967 330 engines, the power gains should be comparable.
The only comparative data I have is the actual Oldsmobile specs for the 1972 350 engine configurations. While the 1972 350 engines are not the same as the 1967 330 engines, the power gains should be comparable.
In 1967, Olds offered both the 2bbl and 4bbl motors in both 9.00:1 and 10.25:1 CRs. The RPO L65 low compression 2bbl 330 was rated at 250 HP. The RPO L73 low compression 4bbl 330 was rated at 310 HP. Unfortunately these are not apples-to-apples comparisons, as the 2bbl motors got the 250/264 cam with 36 deg overlap while the 4bbl motors got the 278/282 cam with 47 deg overlap.
April 6th, 2024, 04:36 AM
