HELP PLEASE. Holley 1920 to Carter BBS

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lopar68

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I have a 1968 Plymouth Valiant 225. It currently has a Holley 1920. Without getting into the whole what carb is better. For my own personal reasons I want to switch to a Carter 1 brl carb. Can anyone please point me in the right direction maybe some parts numbers. I found 1 on summit racing but it says its for the 170. Dont know if it will work on the 225. below is the link to the carb. Any help is much appreciated

http://www.summitracing.com/parts/urm-6-6100
 
IIRC, the 170 carb has a slightly smaller throat size. It will work, but will choke the flow down a bit. Of course the Uremco listing also says it is for a 5.7L engine.....a 350!
 
nm9stheham said:
IIRC, the 170 carb has a slightly smaller throat size.
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Not completely correct. The 170 standart shift had the small carb. The 170 auto had the same size carb (large) as the 225 auto and standard shift. Also I'm not positive, but I thought in 68 they had discontinued using the small carb.
 
The 170, with automatic and manual transmissions, used Carter BBS and Holley 1920 carburetors with a 1-9/16" throttle bore until 1967, when the 170, with automatic and manual transmissions, got Carter BBS and Holley 1920 carburetors with the larger 1-11/16" throttle bore that had been used all along on the 225 (except taxi/fleet which used the smaller size). That was one of the two changes for '67 that caused Chrysler to bump the 170's published horsepower rating from 101 to 115.

The best Carter BBS to pick will be the 1971 item. Originally there were two of them, Carter № 4955s for manual transmission and № 4956s for automatic transmission. Slight jetting differences and the manual-trans carb had a slow-closing throttle dashpot.

The biggest problem is finding one of these (or any of the many other compatible carbs) in good condition these days. Virtually all "remanufactured" carburetors are garbage not worth buying. New (NOS) ones go by on eBay from time to time. How big of a hurry are you in, Lopar68?
 
Dan, I beg to differ about the 170 carb. I don't know what years, had which carbs, and I don't remember the barrel/venturi size. I do have first hand knowledge about the 1965 Valiant with a 170.
When I ran my 1965 Valiant with a 170 in NHRA stock eliminator (1974-1976) I had to use the small carb with a 3sp standard shift trans. When using the auto trans, I ran the larger carb. My useage was the 1920 Holley for the auto, and a Carter with the standard trans. The reason being I could not find Holleys and/or Carter carbs with the correct numbers for the application, except for those. The car actually ran quicker/faster with the auto due to:
Stick had too much RPM drop between 1st and 2nd, and the smaller carb choked the engine more.
 
nm9stheham said:
any idea why they added the dashpot on the manual versions? Easier synchronizing, or emissions??
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The purpose of the dashpot is to slow down the last few degrees of throttle closure to avoid "wet flash" in the intake manifold when you yank your foot off the accelerator—that's when the air's suddenly shut off because the throttle plates slam shut, causing a temporary rich-mixture spike, which causes herky-jerky behaviour if the car has a manual transmission and you haven't stepped on the clutch. It also causes a spike in exhaust emissions, which eventually started mattering when emissions regulations came in. But dashputs were on (some) manual-trans carbs long before the world's first emission regs.
 
Charrlie_S said:
I don't know what years, had which carbs and I don't remember the barrel/venturi size.
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That's why I posted the info.
icon_biggrin.gif
Srsly, though, this what I posted is extensively supported by factory documentation. Occasionally there'll be a typo or an omission or an error in one document, so it's nice when there are multiple documents. FSMs and MTSC books and TSBs and specification breakouts from the carburetor makers themselves, etc.

My useage was the 1920 Holley for the auto, and a Carter with the standard trans. The reason being I could not find Holleys and/or Carter carbs with the correct numbers for the application
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OK, but that doesn't mean the factory didn't put 'em there, it just means you couldn't find 'em, right? Or am I misunderstanding you?
 
slantsixdan said:
OK, but that doesn't mean the factory didn't put 'em there, it just means you couldn't find 'em, right? Or am I misunderstanding you?
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I think you are misunderstanding me.
The point I was trying to make, was the 1965 Valiant, 170 cid stick trans, had the smaller carb, whereas the 170 auto and 225 auto and stick used the larger carb.
You are correct about my paeticular usage, I could not find the correct small Holley or the correct large Carter. NHRA required the correct numbers on the carb, for the year and application. For example, I got bounced one time, in tech, because I had a Holley 1920, with the numbers for a 1966 170 auto trans, instead of a 1965. Carb was the same just different numbers. So the correct number was a critical issue.

PS: the quality control on these Holley carbs was so bad, you could measure the barrel and venturi size, of several carbs and get widely varying sizes. Most were smaller then spec size, but I found one that was very close to spec, and the car would run two tenths quicker with that carb.
 
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