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Discussion Starter #1
So, the adventure with my '81 continues. It's getting better, for those who may have seen my occasional posts. Next week, it goes into the shop for rewiring, and rechecking all the oil leaks. I may have to replace the timing cover that my old mechanic put on when I got it.

On to my real questions...when I got the El Camino originally, I was told that it had a 267 engine (not the 350 that was advertised), and I made some modifications to the engine on that basis. It's been running pretty well, and my idle issues went away when my current mechanic found that there was a tiny vacuum leak when the new intake manifold got put on. I now know that what I have is actually a 305 engine. It runs pretty well, and I have gotten up to 19 mpg out of it. I was reading up, and apparently, it's calculated that a 305 small block runs at its best with a 600 cfm carb on it, and what I have right now is a Holley 390 cfm.

  • Would I benefit by putting in something like a Holley 4160 or an Edelbrock 4106?
  • What do I gain by doing that?
  • What could I lose?

I'm not looking to do the usual 350 upgrade that everyone promotes. I just want to get what I have running at its best.
 

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What is your goal? MPG or higher performance? For me, I'd stick with the "runs pretty well" small Holley because moving to the 600 Holley is not going to turn your 305 into anything massively high performance. Yes, it might accelerate a little better but MPG will suffer.

Rick
 

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Discussion Starter #3
My goal is to have the engine running at its best, and most efficient. I would expect, and hope, to have somewhat better acceleration and power, but wasn't sure on the impact to MPG.
As it is now, the engine handles 70 mph at 2000 rpm without any struggle. Even when I really push it, it never really goes over 3000 rpm.
 

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Why not stick with the tried and true Quadrate. Nothing is going to get you better fuel mileage and they are just basically foolproof. We have a bunch of members on El Central that will attest to that. Order you one from Mountain Man Carbs and InJection ,set the idle speed and DON'T touch the carb after that. I have one that I have been running about 7 years that runs exactly as it did when I installed it. AS for your timing chain cover, if its a chrome cover you will NEVER stop it from leaking. The gaskets and sealers just won't stick to that chrome. I installed a painted steel cover and never another leak.
 

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Discussion Starter #5
Yeah, the timing cover is chrome. I already mentioned the possibility of getting a better one when I dropped it off today. I expect my short list will take all week.

So, I asked my new mechanic the same question, and he echoed part of what has been posted here, and offered what he felt was the better solution.
1. The 305 does run best with a 600 cfm carb on it, but I don't currently have one installed.
2. If I have no real complaints about how it's running, and I don't, then why even do an upgrade at all.
3. If I decided to upgrade, for the money, he suggested I just to right to fuel injection and be done with it.

I'm good for now, and this rewiring is going to cost a bit of money, so I can wait for a later time. Thanks for the input.
 

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Why spend the kind of money it'll take to put FI on it when for about 250 you can have what runs so good on these engines. f you still have the computer on it you can get a fresh feedback carb built by MtN Man or throw the computer in the trash and put a non feedback carb and non comp. distributor on it . As far as the timing chain cover goes you may can try to have the back of it bead blasted . I started to do that with mine but its too much of a chore to pull that cover to take a chance. Throw it away and get a plain original painted cover. Good luck to you.
 

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Discussion Starter #7
Remember that I don't do my own work. It would be $250 PLUS labor. I also don't know what is really left under the hood and dash on this car. The guy who had it last did a lot of goofy and questionably creative stuff. There's wiring hanging out under the dash, and a massive bunch of dead wires under the hood. My first priority is getting things clean and organized...not to mention functional.
 

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I vote for a new carb altogether. I can read......but you CAN install a new carb without paying someone to do it for you. There are countless youtube videos, and internet info to help you. And I promise, there isn't much that's easier to swap on than an Holley 4160 Carb. I mean, for real. It's quite literally held on with 4 nuts. If you are planning any real use of an antique car, super simple repairs like a carb swap REALLY ought to be on the learning agenda. And even if you refuse to do it, any shop worth their salt would not charge much to install it. One hour shop time would be the MAX for a carb swap. I installed the 4160 as shown in maybe.....25-30 minutes. From start to finish. Holley sells the 4160 as a direct replacement carb, 100% set and ready to bolt on. They even claim little to no tuning necessary. Put it on and go. Nothing wrong with a Quadrajet, I just happen to like Holley. And for the price, you get a brand spankin' new carb.

Search the net and youtube. Lots of people LOVE the 4160 for 305 engines. And since your going from a Holley to a Holley, install will be that much quicker. And at least in MY case, I never touched a thing on my 600, other than to lower the idle, maybe 1/2 a turn. I promise, I love my Holley.
 

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Get some of the Quad users on this site to chime in and let you know how their experience with it is . A new carb ? Really, the quad is as proven a carb as there has ever been. The rebuilding by Mtn Man is as good as you can get, but then, its up to you of course.
 

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Q-jet. Built by a professional like Mountain Man. Avoid parts store remans, they’re iffy at best. GM spent mountains of money making sure they ran right.
Patrick
 
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