Sam, mine were adjusted a few thousands loose cold before break in, then I set them 0.001 loose from spec warm. I also tried dead on spec warm adjustment. I'm not hearing any difference in sound. The performance has been good consistent at all these settings, though I'm told that a bit loose sometimes runs better.

Many years ago I had a '70 Valiant and that slant seemed quieter to me, but hey, that was about 30 years ago and it certainly did tick. Memory is notoriously unreliable.

I do think the sewing machine sound of a slant is unique, does give it character I suppose.

brian

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https://tinyurl.com/yynpj4v2

Sam, you said earlier that your issue has occurred consistently in the past regardless of induction types. I think you need to reconsider that it is a temperature issue. On an extended 70mph run, the engine is most likely operating relatively "cool". If you were to come to a stop immediately after like you are describing, I could see where the fuel is not mixing/atomizing at optimal temperatures. What t-stat temp are you running? If it is a 180F, this might be the cause. Try a 195F t-stat and see if you still have the same issues. If you are already running a 195F t-stat, please disregard my ramblings and theory...

Brian

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Flyin' Brian

74 Duster, 225, rear-mounted blow through turbo at 12psi boost, street/strip car
"Sixy Beast"

No.

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

I am currently running a 180, however, I have used a 195 in the past, and think this condition was the same. I cannot swear to this, but almost certain. Thanks for the thoughts. What valve lash adjustments do you use, Brian?
Sam

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My slants were the same- poor idle & low power after a high speed run. I always figured it WAS a temperature problem, specifically manifold temps. You put a lot of heat into the manifolds during a highway run, but while you're moving airflow over (& fuel/air inside the intake) keep things manageable. Come to a stop, and intake temps shoot up- (carbs don't like too much heat).

You might try a "cold air" intake hose to the air cleaner inlet.

This was one of the reasons I did EFI & headers on my last Dart.

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63 Valiant Wagon
225 - 4 bbl

On ANY aftermarket cam, I always start with the recommended setting from the manufacturer, but I always end up somewhere else. If it idles poorly when hot and I feel everything else is in good shape, I back off the cam lash in 0.002-0.004" steps until the idle smooths out. Note that INT/EXH can be off by different amounts. Yes, I am talking about a full heat cycle and driving around with each new setting. If there is no noise, they are too tight, in my experience.

I might start with 0.018"/0.025" next and see if idle improves, then go up or down from there. For a hipo cam, I usually end up looser than manuf specs.

Interested to hear your results.

Lou (from Minot, ND in the 64 Dart, about to cross in to Canada)

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Home of Slant6-powered fun machines since 1988

Did you get lost on your way to Bristol?

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Isn't Bristol in Alaska??

Lou

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Home of Slant6-powered fun machines since 1988

Lou, I wonder how close we came to each other. I flew into KC on the 6th and drove to central Kansas. Thanks for the advice. I will try setting them .04 looser and see how it goes.
Sam

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Not so close. I went I-74 west from Indy, then north through MN and then up through ND to Canada. In Calgary now and will see Sandy tomorrow night.

Had to develop a tune for high altitude with this old MSI ECU. Hope to solve that with MSIII. Your thread inspired me to lash my valves again and I tried 0.002" tighter as I was at 0.030"/0.032". Seems OK after 30 mi.

Lou

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Home of Slant6-powered fun machines since 1988