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Hello everyone,

I was curious, what would the hp and drive ability difference be on a 3x2 setup vs say a 750 Holley with a performer rpm intake? The engine in question is a 440hp 383 sbc.

I was thinking it might be a fun project to scrounge the parts and rebuild the carbs.

Thanks
Jordon
 

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Honest answer, chances are at best you might get the tri-power set up to run as well as a single 4 BBL. The key would be a well designed tri-power to work with your combination (some of the SB Chevy 3X2 intakes are really pretty poor designs but work passably well on small inch lower HP applications).

On the plus side is a big WOW factor and there is nothing like kicking the end carbs open.

If you still interested building the carbs, I pretty much covered what's needed on this site.

http://www.clubhotrod.com/forums/showthread.php?t=26886
 

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After looking over my post above, forgot to mention that from personal experience normally on anything over 325 CI, a Large Base Rochester (rather than a small base) is almost required as a Small base will end up starving the engine.

You will most likely have to modify the manifold and/or build a thin adaptor plate to make the large base fit (no big deal really, I've done several of them).

The trick will be finding the right large base carb for your engine. They put the large base carbs on engines as small as a 231 Buick and large as the 455 Buick and Pontiac engines. What you need to hunt for is one off a 455 BOP, or 400 inch Chevy small block or 400 Inch Pontiac (or something of about that displacement) as a starting point.

Addtionally, on all the SBC Tri-Power intakes I have come across you cannot run a Chevy HEI distributor as it will not clear the rear carb. You will need either a stock distributor (say converted to electronic) or something like a Mallory Unilite.
 

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aka Duke of URL
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1957plymouthhemi said:
Addtionally, on all the SBC Tri-Power intakes I have come across you cannot run a Chevy HEI distributor as it will not clear the rear carb. You will need either a stock distributor (say converted to electronic) or something like a Mallory Unilite.
THREE DEUCES ARE B ! T C H E N !

How about the HEI distributor model that has the remote coil?

Now to take you to task... :p

Why is it that you don't have that pretty 57 PLYM as your avatar?
 

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I can't see it being a big deal. Just be patient. Drivability wise you're ridin around on a 2bbl for most of the time. The ends are mostly "dumps" w/o idle circuits. Go for it. Lots of info out there.
 

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Hates: Liver. Loves: Diesel
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One of the mags just did an article about the brand new BG triple duece carb setup. I gleaned two things from that article.

1) the multi-carb setup made less power and torque. Not a lot less, but 5-10 on each.

2) one of the things they said (paraphrased) was something like; multi carb setups have long been known as a wow setup that is more show than go.

Just for my personal taste, I love the look, but why reduce power and add all the tuning headache?
 

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1967 Chevrolet Biscayne 10-71 blown 433 Big Block Chevy, T400 & 12 bolt 3.73 rearend
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The 421 I built for a customers GTO produced more hp and torque on the dyno with a single carb than the tri power. The owner wanted the tri power for the wow factor. He told me " It's a 64 GTO, it has to have 3 deuces". So that's what he got. It took a lot of work on the center carb to work with his engine combination. After the idle and jetting were dialed in, it works very well on the street and looks great.

Barry
 

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curtis73 said:
Just for my personal taste, I love the look, but why reduce power and add all the tuning headache?
It's been known for years that a single carb will almost always generate more power than a multiple carb set-up. But, really now, how many people are going to notice a 5-10 hp loss at upper rpm? Not many I would guess. Besides we are talking about street machine application, not racing where every hp is craved. Wow factor often plays far more importance in a street car than max hp.
As far as tuning headaches.... if you have to continually adjust a multi-carb system, either it was never set up correctly or there is a problem in the carbs. I ran mine for 3 years and never did anything after initial set up. Drove it as a daily driver. I can tell you that when people saw the trips, they didn't even notice the full cage of tilt forward hood system....they were drawn to the glitz...like moths to a flame.
 

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In the 50's either dual quads or Tri-Power was the hot ticket in carburation simply because the single 4 barrels of the day could not provide the amount of airflow needed for the engines as they grew bigger and turned tighter.

Multiple carbs became associated with more HP and in large part due to that manufactures marketed that thru late 60's early 70's with (of memory serves correctly) the last 6 Pax engine ......the 340 and 440 Mopars. While these engines were rated at more HP than their single 4 BBL counterparts most people don't realise that the gain was due in large part to the higher compression and hotter cams the factory slipped in.

I will readily admit that tri-power is my favorite induction, I just enjoy the challenge of building the carbs and getting them set up (as mentioned by woods428 once they have been properly dialed in you just drive them).

Especially for the first timer building his own set of carbs it can be a frustrating adventure. I know a lot of people who had big plans for a tri-power set up only to give up in frustration at not being able to get it right.

If your up to it though I'd say go for it.
 
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