[Curchthecat]

Hay guys I have a 1960 catalina that is still all original for the most part. I'm wanting to swap my 2 bbl intake with a 4 bbl but I can't find the correct intake for it. I know it has the be the 57-60 if anyone one has one that they are willing to sell please let me know. Thanks in advance

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[tom s]

Some after market intakes like Offys are made to fit 55-60 and 61-64 with a soft plug change on the mounting flange.Maybe search Ebay.Tom

[Sirrotica]

Depending which carb you intend to use makes a difference in what stock cast iron intake you try to find. 1957 still used a Rochester 4 jet carb, but 58 was the first year for the Carter AFB carb. Myself I would try to find an AFB intake because they were larger flow CFM sized. You might try to find a complete matched carb and intake setup from 58-60.

The 1960 cars had a few 2 bbl setups and also the gas mileage option had the tiny Rochester that also came on the SBC engines, I believe it was dubbed the 425E, the E standing for economy. This engine was rated quite low and had 215 HP. They also had the larger Rochester carb, and if I remember correctly there was a premium fuel 2 bbl engine also.

Compression ratio was also subject to a few options. And of course they also had a few different camshaft choices among the 2 bbl engines also. It may be a good idea to find out which 2 bbl option you have to get an idea of which camshaft and compression ratio you currently have before upgrading the induction side.

If you get the block code off of the engine you can break down what came on the original engine, and what options you have for upgrades.

[694.1]

Sirrotica's knowledge far eclipses mine but the AFB was a mid year offering in '57.
I changed my '57 from a 4 Jet to the correct AFB.
Idles the same, starts the same, pulls the same. Hot or cold.
Just a tad disappointed!
But the AFB is a little lighter

[Curchthecat]

Mine is the big 2 bbl with the 10.6:1 compression. I currently have a adapter to run a 4bbl 4226 holley. And it does run like it has the more aggressive cam. It runs perfect currently even after it was sitting since 1983 with 39,246 miles. It was locked up when I got it last year but it did free up easy and never smoked out the exhaust. She's a survivor.

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[Sirrotica]

Originally Posted by 694.1

Sirrotica's knowledge far eclipses mine but the AFB was a mid year offering in '57.
I changed my '57 from a 4 Jet to the correct AFB.
Idles the same, starts the same, pulls the same. Hot or cold.
Just a tad disappointed!
But the AFB is a little lighter

My father owned a 57 Chieftain, and it had the Rochester 4 jet 4GC, I remember him rebuilding it one Saturday afternoon, then taking me, and another neighbor kid for the test drive. I was really impressed with that test drive........LOL

I was basing my post off of that experience, but as you said they do also list an AFB along with the Rochester as both available. If you pay attention you learn something new everyday. TY for bringing that bit of info up
Likely Pontiac spec'd the Carter to the same spec as the Rochester to keep everything equal, so likely there would be zero gain swapping. I'll bet if you jetted the AFB up a couple sizes, you'd likely see some performance gain. Factory jetting is almost always a little lean.

I've been exposed to both carbs over the years, and hands down I'd always opt for the AFB if I was looking for better performance, and potential. Carter made a ton of AFBs almost a different carb for every application an AFB was used on. When junkyard hunting for cheap performance we'd likely look for Buicks because they used the larger carbs.

[Sirrotica]

Originally Posted by Curchthecat

Mine is the big 2 bbl with the 10.6:1 compression. I currently have a adapter to run a 4bbl 4226 holley. And it does run like it has the more aggressive cam. It runs perfect currently even after it was sitting since 1983 with 39,246 miles. It was locked up when I got it last year but it did free up easy and never smoked out the exhaust. She's a survivor.

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You'd definitely see an improvement ditching the adapter, huge strangle with that adapter. Also Pontiac 4 bbl intakes are usually position the carb at a more favorable position, (higher rise) than the 2 bbl intakes.

When running restricted circle track classes that required a 2 bbl carb, and a factory cast iron intake we would use a adapter to run a 4 bbl intake because of the better carb positioning. The adapter on the 4 bbl intake also gave a slight bit more plenum volume than running a 2 bbl intake.