This is an interesting thread! I was thinking of the Holley 4165 as a replacement for the Q-Jet on my 1974 base engine with TH400. In checking the Summit site they list several models of 4165 and 4175 carbs but under "applications" they show ranges of 1966-70 and 1975-78. What is different for 1971-74 and why is a model not available? Are we into the transmission controlled spark (TCS) area (that I have removed). I would guess that from reading above, the 0-6210 with divorced choke would be a good choice but it has mechanical secondaries And apparently vacuum is better with the automatic transmission. I would appreciate comments.

 

a little history.
1970 last year before EPA clamped down, c3's got 17-20 mpg typical
1971-1974 some epa rules but no cat converters
1975-1981 up cat conv. 12-13 mpg typical
the way they met epa was to lower compression and make the engine run hot. You can simulate this by lowering base timing to ~4 BTDC and turning the idle screw way in to get it to idle. While it will suck lots of gas, the tailpipe was so clean, it took twice as long to commit suicide.
They also added EGR which made it suck even more gas. The more gas the less it "polluted". There is more, but i'd throw up.
So the best carbs are 1970 legal for performance and mpg. If u look at todays SUV's they average 14 mpg.
Back in 1970 the US fleet of station wagons did better with a carb. There has been no improvement with EFI, BUT the fumes from the tailpipe take MUCH longer to commit suicide.
There has been progress, some c-4-5-6 get 30mpg on the highway. But this is from OVERDRIVE and other sensible things that wern't tried with carbs(carbs were abandoned and not tuned for lower than the 4165 's 1500 rpm cruise speed.)
VS is for those that have no idea what the gas pedal does to the carb, and don't want to learn how things work. IMO they figure if u drive an automatic, U R not performance oriented. In my case, i found a beautiful 72 at the right price but it had a TH400. I would not pass on the car despite my performance orientation, so the 4165 works fantastic on it.

 

I have two new remanufacted q-jets,that I bought for my 69 427.I got them from pep boys.One has never been out the box.125.00 each.
or take them both for 225.00
jake
770 987 1635
Ga.

 

Not had the motor in the car yet, not sure how much rubber line from frame to pump? is there room for a filter? anything wrong with a filter before the pump? thanks

 

Ideally you would want the inline filter as your "last line of defense". ie: just before the carb. In the real world, though, you have to put it where you can. You shouldn't have any problems as long as there is a filter somewhere in the line....

 

4165 has a built in filter. that works fine with a new tank/lines. An old tank/lines will plug that small filter quickly due to rust, then u need a big filter at the carb entrance. dont use small internal one at all then.
filter before the pump is not wise w/stock pump.

 

Later cars I have owned won't do that. 74 F250 pickup 390-4sp Autolite 2bbl, it got a solid 12-14. I changed to a Holley 4bbl and a T-bird intake and mileage was the same, my dad still kids me about my great mileage improvement. 83 Chevy K20 pickup with 350 Qjet and 700R4 overdrive was 14-16. Changed to a TPI engine from a C4 and it jumped to 16-18. Same exhaust, same transmission, same everything. 72 Pontiac Grandville 455 Qjet was 12-14. 71 Eldorado convertible 501 Qjet was 12 no matter what you did. 77 Bonneville 350 Qjet (Pontiac) and TH350 got 14-15.

Do you have any evidence that cars from the 60s got 18 mpg or that '70 Corvettes got 17-20? I have had and known several stock cars from that era that got nowhere near that. I had a boss with a 68 307 powerglide Impala -stone stock grandmas car. Single exhaust, 2bbl, kept in good tune. It got maybe 12-14 mpg. My good friend in high school had a '69 Javelin 290-4sp, stone stock but added dual exhaust. now granted we ran the crap out of it, but it was lucky to get 14 mpg. My grandmother had a 70 Buick Wildcat 2 door 455 q-jet, automatic of course. She ran Hi Test gas and no way it broke 15 mpg. I built an engine for a friend with a 67 Camaro, 327 Q-jet, powerglide. Adult owned it's entire life (his father in law bought it new) and tuned meticulously. It also will not break 15 mpg. Also I have some knowledge of a 68 Cutlass, 350 (Olds) Qjet, 2 speed auto and a '67 Mustang 289 2bbl, C4 auto. They also get less than 15. I would love to see some actual evidence of the numbers you are showing. IMHO most of the improvement in MPG is from overdrive transmissions and fuel injection. If you don't want or like Fuel Injection, fine. But I don't see how you can make some of the statements that you are making. I have nothing against Holley, I have had them and they are much easier for the average person to tune than a Qjet. I have had good luck with Qjets, tuned right they are wonderful. My .02

 

mark
thanks for your reply!
I speak from my own experience. i'm 57. i was there.
Sure, there were plenty of gas suckers out there.
My friend had a 67 pontiac dual quads that got 6-7 mpg
I had a 67 cuda 318 automatic. on a trip NJ to MA it got 25.9 mpg! but usually it got 18. My Dad'd 67 289 got 18 he bought it new. My 61 vette, in 75 got 20 on the highway, 22 w/55 jets. Why would a newer vette thru 1970 get poor mpg? Even my 76 c3 in 1980 w/dual exhaust no cat got 17.6
I like efi, it just costs too much, and is too hard for many to troubleshoot or modify.
I see u gained 2 mpg with a TPI. good for you. The TPI is a small runner that limits HP. A SP2 dual plane does the same thing; better mpg but less max hp(if that is your thing). Again, no need for efi if and only if the right carb combo is used. I would expect the same improvement with a 4165, an 83 qjet is a gas sucker too.
I may add more later.............

 

I had a 67 GTO with a tri-power set-up that got 8-10 mpg under hard driving, I never found out what easy driving would have got..

Waiting on fed-ex to drop my carb off at the house, monitoring the status from work! Its getting close, you can guess what I will be doing this afternoon..

Dec 8, 2009 8:36 AMOn FedEx vehicle for deliveryJEFFERSONVILLE, IN
Dec 8, 2009 6:35 AMAt local FedEx facilityJEFFERSONVILLE, IN
Dec 8, 2009 2:49 AMDeparted FedEx locationGROVE CITY, OH
Dec 8, 2009 12:28 AMArrived at FedEx locationGROVE CITY, OH
Dec 7, 2009 7:33 PMLeft FedEx origin facilityRICHFIELD, OH
Dec 7, 2009 2:20 PMArrived at FedEx locationRICHFIELD, OH
Dec 7, 2009 12:02 PMPicked upRICHFIELD, OH

 

[QUOTE=markdtn;1572362764]Later cars I have owned won't do that.>>>>>>> DO WHAT?
.

74 F250 pickup 390-4sp Autolite 2bbl, it got a solid 12-14. I changed to a Holley 4bbl and a T-bird intake and mileage was the same, my dad still kids me about my great mileage improvement....>>>>>>>>>>>>>>>>>>.... Wrong carb i bet. 4165?
83 Chevy K20 pickup with 350 Qjet and 700R4 overdrive was 14-16. Changed to a TPI engine from a C4 and it jumped to 16-18. Same exhaust, same transmission, same everything.>>>>4165 should give same results.
.
72 Pontiac Grandville 455 Qjet was 12-14. 71 Eldorado convertible 501 Qjet was 12 no matter what you did. 77 Bonneville 350 Qjet (Pontiac) and TH350 got 14-15.>>>>>>>>>all sound normal to me. anything 1971 or newer went into the mpg abyss.

Do you have any evidence that cars from the 60s got 18 mpg?>>>>>>>>>>>>>>> On the AP wire there were some articles about the US mpg not going up in ~20 years. That got me thinking about modern "improvements", but i didn't save the article.
.
I have had and known several stock cars from that era that got nowhere near that. I had a boss with a 68 307 powerglide Impala -stone stock grandmas car. Single exhaust, 2bbl, kept in good tune. It got maybe 12-14 mpg. My good friend in high school had a '69 Javelin 290-4sp, stone stock but added dual exhaust. now granted we ran the crap out of it, but it was lucky to get 14 mpg. My grandmother had a 70 Buick Wildcat 2 door 455 q-jet, automatic of course. She ran Hi Test gas and no way it broke 15 mpg. I built an engine for a friend with a 67 Camaro, 327 Q-jet, powerglide. Adult owned it's entire life (his father in law bought it new) and tuned meticulously. It also will not break 15 mpg. Also I have some knowledge of a 68 Cutlass, 350 (Olds) Qjet, 2 speed auto and a '67 Mustang 289 2bbl, C4 auto.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>Lot's of poor mpg. I don't "run the crap" during a max mpg test. I can get 4 mpg doing that I am talking cruising mpg usually. I never saw such terrible cruising mpg that you say you got. Did you set the timing as per the manual?

 

is the 71 together and ready to drive?

 

I don't think I have ever read such garbage.

So you think the pinnacle of the air/fuel mixing device was a carburettor designed in the late 60's and fitted at the beginning of the 70's?

You also believe it out-performs modern injection.

What a crock.

As for your SUV comparison, a C3 averages around 1.75 tons, an '09 Tahoe weighs around 2.75 tons.

That's nearly a 40% weight increase, which means if the MPG is the same the engineers have managed to get 40% more efficiency from the engine/injection to keep up with the weight.

As for the idea that carbs actually lost performance after 1970, LMAO. Many carbs were the same in 1974 as they were in 1964.

The reason performance and MPG dropped in the early 70's was because the manufacturers simply bolted smog devices onto what were already ancient engine designs. It had very little to do with the carburettor, rather just simple engine efficiency.

 

Nope its still just like it is in that pic I posted, all hooked up to run on the stand, but I have had the dang thing a year and only had it running good for a couple of starts till carb troubles shut me down again and a again. Once I get all the bugs worked out and get my engine comp. painted and back togther I am dropping the BB and 4-speed in. I'm gettin closer, I had back surgery and been down for a few months.. wont be long now! I'm going home as soon as fed-ex status says delivered!

 

The reason performance and MPG dropped in the early 70's was because the manufacturers simply bolted smog devices onto what were already ancient engine designs. It had very little to do with the carburettor, rather just simple engine efficiency.[/QUOTE]

Golden
we both agree!
New engines get better mpg from:
roller lifters,
roller rockers
low friction rings
fans that stay off until 228F
Steep overdrive
many speeds like 6
etc.
but your other response, to be so far off, honors me!
Yes u put wrong words to my thoughts!
So, you are fired Like Trump would say.

 

If I've misunderstood you Matt, please explain?

Oh and as a side note, my 350 manual can get up to 24-25mpg with a 625 cfm Carter Comp Series.

 

In case anyone missed my point:
1. the 4165 can't be beat in terms of LOW COST, MPG, POWER and FUN to drive.
2.
I can compare it to converting to EFI, because YOUR GAS SAVINGS WILL NOT LIKELY PAY FOR THE EFI EVER, not if you don't lose HP (with a cheap old unit).
Show your math if you disagree.

 

OK U got your job back! That is my point; a carb can get good mpg.

 

made a new emo-con or what ever they are called..lol

 

Wooo Hooo fed-ex guy left a christmas present on my door step! I'm 44 and this is the first brand new carb I ever bought for one of my old cars.. I bought dozens and dozens of remans for my customers in the 80's and 90's but this has me excited as a kid with a new toy.. Gonna turn on the heat in the garage and look over the instructions for a few while it heats up, then I'll be on it and hopefully fire it up soon! Thanks to all you who helped me out with advice.. I'll let ya know how it goes here in a bit.

 

Now that to me sounds like you're saying that a 1970 carb is the best you can get.

It also looks like you're saying that the average MPG of an SUV today is worse than a 1970's station wagon yet a modern SUV weighs at least 20% more than a 70's station wagon and has a much more draining aircon and electrical systems as well as being 4x4.

The carburettor is a great piece of engineering but compared to injection it's like trying to compare a musket with a Glock.

I agree with you about the relative costs of a new carb against an injection system but injection isn't just about MPG, it gives better cold start, smoother running, better pick up, improved acceleration and at least a small gain in BHP and nearly always an improvement in torque.