Im switching from a holley 1945 carb to a holley 1920 carb. Is there anything I need to change in order to use the 1920?
Thanks

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Ronnie
http://www.cardomain.com/ride/2714941

Yes, depending on the year 1920 you have there may or may not be a fuel vent line that goes to the canister.
Also, I shortened the choke rod. I reshaped it by putting a "Z" bend in it and it works great!
Since I went to the 1920 my car has never run so good. In fact it is very good! My mileage went from 18 to 22 mpg in the winter and 24 plus mpg in the summer.
One other item, do Slant Six Dan's fuel line mod and bring the line up over the valve cover from the fuel pump to the carb. The 1920 fuel inlet is on the valve cover side. Remove the old steel line, it just adds to the heat soak bad starting problem when hot.

For the record I went through (3) 1945 carb's and each one developed a vacuum leak that would not go away. I rebuilt the last one three times and had the others professionally done at $200 each time. The 1920 is much simpler and easier to rebuild if needed and much cheaper!

Send me you email and I can send a few pictures of the mod.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Back up a couple of steps. Are you bound and determined to install a 1920 carb in particular for some reason? Or are you trying to get good, reliable carburetion in your car, which is presently suffering from some variety of carburetor-related ills? The latter is a more realistic, more reasonable goal. What-all, exactly, would you like to achieve in the end? Note the improvements Aggressive Ted saw were due primarily to going from a carburetor in bad shape to a carburetor in good shape, not due to going from a #1945 to a #1920.

The amount of adaptation required to install a 1920 in place of a 1945 depends on what exact 1920 you are trying to install, and how much of your car's original emission control equipment you're keeping. If you want to keep the EGR functional, you would need a 1973 (only) carburetor. If you're keeping the evaporative emission control canister (and you should), then you'd need a 1971-up carburetor. If you're keeping the thermostatic air cleaner (another good thing to keep), you'd need a 1970-up carburetor. There are other factors to consider, too, such as adding a stronger throttle return spring if you use a pre-1974 carburetor, because 1974 and later carburetors have built-in throttle return springs and so are equipped with weak secondary "helper" return springs that aren't usually adequate to pull the throttle all the way closed. Choke modification may be necessary; bending the original choke rod is schlock. Do it right instead.

Again, I encourage you to start from the start (what exactly you want to achieve) rather than starting from the end (which carburetor to install).

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

The only reason I was going to get a 1920 carb was because I heard they were all around better. My 1945 needs rebuilt and if I could get a 1920 carb pretty cheap then I was going to switch over. Right now my car gets around 10 mpgs and I wanted to improve that.

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Ronnie
http://www.cardomain.com/ride/2714941

Yeah, I would say 10mpg probably points to some pretty serious carburetion issues! The main reason why 1945s are hated isn't because they're badly designed. There are many aspects of the 1945 that are better engineered than the 1920. The float system, for example (stallproof in left turns), and the overall casting design (no gaskets below fuel level). The main reason why the 1945 gets a bad rap is that these carbs were initially calibrated for emission control rather than driveability, and installed in vehicles with a lot of first-generation emission controls that seriously hurt driveability and economy. But jets can be changed, adjustments can be tweaked, and emission controls that only existed to squeak the cars past unrealistic Federal exhaust emission type-approval tests can be removed or updated as appropriate.

I'm not necessarily trying to talk you out of a 1920, but fact is, it will be more difficult to find a good 1920 than a good 1945, and easier to swap on a good 1945 than to swap on a 1920. I'm not 100% sure what I'd do in your position, but I think I would probably swap on a good 1945, dial it in (configure and adjust it) carefully, and take a hard look at some of the engine's emission control devices (OSAC valve, EGR) as well as the timing curves. Send me a(nother) PM if you like.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Another thing to augment Dan's line of thinking is to also get a vacc. gauge (even a Harbor Freight one if you are poor...)... and see if your Vacc. advance pod on the distributor is still functional (most of them after 30-40 years of abuse are toast and are a vacc. leak...)

If it won't hold vaccuum, some of your economy can be put back by getting a new pod and replacing the old one... (There's one member on here that I replaced the pod on his distributor with a 'spare' I had lying around that 'just worked'... I got an e-mail a week later that said he usually filled up every week going to school, suddenly he could go a week and a half...)

also, the 1945 is an easy carb to rebuild, about $25 for a kit, a couple bux for a bucket and a can of lacquer thinner is the poor man's carb dip and rebuild set up... maybe a few more bux if you pull the jet and find it's a 58... in which case, it's time to up it to a 60 to be close to the 1976 model year (and adjust linkage per the 1975/76 listing in the instructions)...




-D.Idiot

Before I went to a super six I had my 1945 rebuild by a friend and had the jet size upped 4 sizes, 68 to a 76 or 73 I think, and WOW did it go, but it was still guttless on the freeway at 65mph. I liked my 1945 but in the persuit of power.................

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

Do you remember where you got the jet?

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Ronnie
http://www.cardomain.com/ride/2714941

He had two or three old 1945's laying aroud and used the jets out of them due to them being bigger and all but it reallllllllly liked it. I asked what they came from and he didnt remember. Maybe a gm ? dont know off hand.

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it's like a vw, sounds like a million miles an hour but goes really slow. (for now)

Ill check around

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Ronnie
http://www.cardomain.com/ride/2714941

Holley 1920, 1945, 2300, 2305, 4150, 4160....yaddah, yaddah...

All use the same jets... so if your local auto parts store can get jets for a Holley 4 barrel (tell them you have a Holley list number 1850-3) and you need one jet (or two if they only sell them in twos) then pick your number

For Holley 1920 #58 'max'
For Holley 1945 #61 'max' (or 612 for the 1976+ group with the 'close' tolerance jet...)

-D.Idiot