I am getting ready to rebuild the holley 1945 on my truck.I have a walker carb kit[made in usa].Are there any mods for the 1945?I have read posts and used search function.Most mods are 1920 related.My main goal is mileage.The engine is stock except for HEI and fuel line mod.The truck has an auto trans with lockup.I currently get 14 mpg.It got 10 mpg before HEI and fuel line mod.Thank you for any ideas.

oldblue,

The 1945 is not very easy to modify like the 1920 however, some folks will change the main jet and replace it with a bigger one. I believe my original one that came in my 1974 Swinger had a #58.

What jet does your have in it? #??

I installed a #61-2 in mine a got a little better mileage which kept me out of the power valve allot more. It went from 18 mpg up to 21 mpg.

The floats usually come deformed in the box. You have to fiddle with bending them so they don't hang up on the float bowl sides. You really can't tune the power valve much like on a 1920 or do much with the air bleeds. I set mine aside after wearing the screw holes out from taking it apart so many times. The 1920 Holley Economaster is so much easier to tune and faster to re-jet....for a one barrel I find it easier to work with. It is not as big of a heat sink either. My 1945 used to boil over now and then on really hot days. It didn't matter how new the needle and seat were or how low I adjusted the floats. It just like boiling over on 90+ days.

Maybe others have better experience with the 1945. I have (3) 1945's, one fairly new, but prefer the R7585 1920 Holley Economaster. It is much more responsive and never boils over......

I have heard of some folks getting up to 30 mpg on long drives at a steady pace across the US in Diplomats, Aspens and Volare's

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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

Thanks.I know a 1920 eco would be better.But $13 for a carb kit is about all I can afford right now.Carb is still on truck so I will find out the main jet size when I tackle it.The vacuum at highway speeds is usually 13" to 7".Around town the vacuum can go as high as 15".At idle in gear it is 13".17" in park.So the power valve is in at what vacuum?

I would recommend installing a brass float while you have the carb apart. That's Walker #100-48 (the nitrophyll float, which if you don't go to brass should definitely be replaced, is #100-13). It's probably true that you're more limited in the mods you can do to a #1945 relative to a #1920, but the #1945, by design, fixes a lot of the shortcomings of the #1920. So I don't know that I could pick which is the better overall design...they both have plus points and minus points (and I don't gotta worry about it much 'cause I have both kinds, new, on the shelf at least until people buy 'em all up! ). Proper jetting is definitely the primary way to dial-in a 1945 to work well with your specific setup, and as Ted mentions, you mustn't assume a smaller jet is necessarily the way to better fuel economy. Most of the 1945s came jetted lean, so you're frequently in the power valve (hint: the Federal emission type-approval tests the cars had to pass in order for Chrysler to sell them when new didn't make much use of the power valve!)

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

Thank you for the part # for float.If I go to a larger main will the power valve stay off longer?Or is only affected by vacuum?I have adjusted jetting on motorcycles before.Mostly slide and cv types.Tuning with a power valve is the "new" variable.

Yes, because it's not lean and causing low vaccuum, it'll have the right amount of fuel the engine needs and will keep the vacc. reading higher...
Holley jets if you haven't been told for the 1920/1945 are the same as the 4 barrel jets so if you need a #61, you can order a pack of 2 from your local auto parts store, FYI.

-D.Idiot

Thanks.I have a holley dealer close.He said he had never seen a one barrel holley before.Probably used to v8 people.

what is the standard 1920 holly jet size? stock..

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Its so nice out side, I think I'll go lay under my car..

Stock jet size depends on which exact #1920 we're talking about; there were many different ones from '62 to '73. Most stock jets were in the range between #53 and #59 or so.

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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 main jets for the 1945 are in what range?Also the vacuum port off carb marked for egr has no reading at idle or throttle open?

oldblue,
From what I have experienced and seen so far are #58 through #62.
I removed EGR and related hoses, switches, etc. on mine and capped the port.

On your earlier question of when the power valve engages, like DI said it depends on the main jet and rear end ratio. Anywhere between 10" and 5" of vacuum. The bigger the main jet the less it comes on........

What rear end ratio do you have? It sounds like your truck is set up nice if the ratio is not too low. My neighbors truck is very similar and has gotten as high as 21 mpg. Most of the time he gets between 16 and 18 mpg around town. He is running a 3.23 ratio.

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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

The rear end is a 3.55 with p 235/75-15s.Rpms at 65 to 70 are 2800.My mileage is about the same on highway as city.I think the power valve is engaged at highway speeds.The vacuum is lower at highway speeds than around town.7" to 10" vs 13" to 16".Plus the aero on a 1982 short bed is none to racy.I have a cold air intake installed.Best mpg I ever got was right after the hei install.It was all country roads 35mph to 45mph and got almost 20mpg.

oldblue,

Sounds like a nice truck. Yes, speed and drag are a big factor on vacuum and mileage. I wonder what jet you will find....hopefully not a #58. It would really help to step it up a few sizes to keep the power valve from coming on at the higher speeds.
With the HEI install, are you running a 74 or newer electronic distributor?
If you are, you may want to do a distributor recurve to get a little more power out of the engine at highway cruise to go with a bigger jet.

Do you know what number is stamped on your vacuum pod arm?
A little fine tuning may get your average mileage up at 50 to 60 mph.

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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

My plan is to do the carb first then the recurve.The vacuum at carb will change when jetting/tuning.When I get the readings with the carb mods then I will adjust distributor.Using the truck this weekend so tuning on carb will have to wait.I will post back when I get time to tackle it.

H'mm. How d'you reckon it? Most '73 and '74 slant-6 passenger car applications used the #3755042/043 distributor, and there are some 1976 distributors, '714 and '082 for example, that have good curves built in from the factory.

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