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Hey guys, i just picked up a 68 396 SS last month. When i give it a little gas it sputters, but when push harder on the gas it runs strong. I dont know where to start to address this and the local mechanics wont touch a carburated motor. Any ideas or help would be greatly appreciated!

Ps, on the spare keys there is a tag that says "poor idle". Im guessing the previous owner took it to a shop with this same complaint, but it obviously was never fixed.
 

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First check timing. If no other obvious problems like vacuum leaks loose hoses etc.
16-18 initial with vacuum disconnected is a good start.
Do you know how to check timing?
If not maybe there is a member close to you that are willing to help you.
 
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Its either ignition timing, or carb tuning. As said, start with the easy one, timing.

If that doesnt clean it up, check FUEL LEVEL IN CARB before you start tuning on it.

Now back to Marcus' question....... do you know how?
 
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No, i dont know how to check the timing.
I would try to find someone that can help you check timing, maybe visit a Cruise night or another car show and ask around? Someone there might know a shop you can use or suggest someone or even offer to help you.
 

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Buy yourself a timing light and a vacuum gauge. Use the timing light to check how the ignition timing is set, and adjust it if you need to. After you do that, dial in the float levels, idle speed, and idle mixture on your carb. Before you bought the car do you know whether it has been sitting for a long time? Does it have old, stale fuel in the tank? If so then it might not be a bad idea to remove the carb so you can disassemble it and give it a good cleaning. What kind of carburetor do you have? Post some pictures if you need help figuring it out.

It'll take a little time and a little trial & error. There are plenty of youtube videos that will walk you through setting your timing and tuning your carb, so take some time to familiarize yourself with those procedures before you begin.
 

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1970 El Camino SS396, VortecPro 467, ATI TH400, Moser 12 bolt /TruTrac 3:42, Hedman headers
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I cannot help but laugh at “local mechanics won’t touch a carbureted motor”…..mechanics …my butt. Go to a local cruise in / car show…talk to the people with Chevelles as to who to trust / help you out of your dilemma and LISTEN, WATCH and LEARN. Learn how to sort good info from bad or your wallet will go flat quickly. Most of the guys on this site got their start this way. Be prepared to spend some money on GOOD tools, a Motors Manual, a Assembly Manual and a Shop Manual for your year will be helpful. Good luck.
 

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Post your location maybe someone nearby would offer to help you or tune it for you for pay or at the least cover their lunch and gas. No one (even relatives) shouldn't have to work for free.
 
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or maybe can refer you to someone close to you. Learning the procedure will help you understand the engine better anyhow. Hey, you may get a batch of old fuel one day, and it start pinging. It be nice to know how to take , say 4or 5 degrees of timing out of it. On the fly.

Good light just under $100. Many dont like the ones with the advance dial, but without it, you cannot tell full timing unless the balancer ( the big round disc at the end of the crank at the front of the engine), is etched with degrees or you install a timing tape. ( which, mine is a half-arsed show car not drag car so I left it stock) Otherwise, with the simple one groove balancer mark and a factory timing tab, the advance dial helps you see how far the advance goes at higher rpms, well past idle.

Which is how most of us set our timing when you're tuning for max power. ( or if like me, the pro who built the engine said to time it at 36 total degrees MAX. )

PS a shopping list:

 

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Bad or faulty wire do prefer to give it up when under a bit more load, so a misfire at part throttle enrichment could find a faulty wire ( or coil) . Maybe check this along with your NEW timing light! :)


PS not to pile it on, but when I broke a plug wire installing it years ago, I went to checking the resistance of every plug wire I touch. So timing light, multi -tester, are all part of the "tool kit', unless you plan on depending on a professional mechanic for everything. If so, gotta find the right one.
 

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You tube is your friend. There's about nothing you can't learn to to do on there. Timing is very easy.

First loosen up a little the 9/16 bolt on distributor.
Warm up engine. Plug rubber vaccum hose to distributor vaccim advance can, I use a screw that fits tight in hose. Shut off engine put Timing light leads on battery, then put spark plug adapter on #1"plug it's the drivers side first plug. Clean off Timing marks on balancer and Timing tab mounted on Timing cover behind water pump. Start engine see where your tIming is set to then set it at least 12 btdc increase Timing by turning distributor counter clockwise. Pick up a Timing light with out one your dead in the water. I'll post a link for nice digital one. It will pay for itself after first use
 

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Depending on the miss, pushing engine harder (more rpm) could cover it up.Have you checked spark plugs? Use a wet rag, touch the headers just off the head for heat or use an infrared thermometer. That can tell you which cylinder has an issue. If you find one that is lower on temp, switch a plug wire.
 

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In addition to everything above, see if someone can help to check your fuel pressure, I had a fuel pump that was putting out way too high pressure. It idled bad as it was literally dumping raw fuel into the carb, but it cleared up and ran fine going down the road. Similar to what you describe. Does it smell like gas at idle?
 

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As said, start with checking timing. Now that you have a classic car, you really should learn some of this. Mechanics now are parts changers, and rely on computers to tell them if anything is wrong.

Buy yourself a timing light. If the engine balancer isn't degreed, buy a set of MSD timing tapes, and install the correct one on your balancer.

Many of us on here can then walk you through setting timing. It is not difficult at all and I am amazed by how many people think it's black magic. Post a pic of your distributor, so we can see what type it is. And post a pic of your carb, as tuning the carb after if need be varies with what it is.
 

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Search for a classic car restoration shop in your area. They will have mechanics that can work on your car.
I second this , In my area there are at least 3 very reputable larger shops that builds engines, builds cars, has engine and chassis dyno's etc.

Or you can learn yourself. You tube has some good content, just need to wade through the bad- become a student. Also can watch all the David Freiburger content on Motortrend, such as Roadkill/ Roadkill garage/Hotrod Garage/ Engine Masters etc. I know they have covered a bunch of tuning on different episodes, from basic timing to dialing in a holley DP.

Where are you located?
 
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