I keep thinking about some header ideas.
Here is a poor image of some 6 into 1 and 2 x 3 into 1 info.
Still not sure where it is going in my head yet.
But I laid out the pulses in a 2 headers system and then a single 6 system.
It seems to me that the additional pulses in a single 6 system would scavenge more completely.
Anyway not done with my theory yet.

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Hyper_pak

Unless your building the meanest, rip snarling Slant that has ever existed, an 1-3/4" primary tube is going to be way too large for any combination you could ever create. Use an 1-5/8" instead....

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There's no such thing as too much cam....only not enough engine!

Not the meanest, but the headers on the Colt are 1 3/4 now.

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Hyper_pak

You'd be faster if you replaced what you have now with 1-5/8"...
1-3/4" are to large for most 300 cubic inch Ford's and Chevy's that make twice the HP you will ever make with a Slant even if you added a turbo. You're leaving a lot of HP on the table with headers that large.....

I think trying a 6 into 1 header is going to be a mistake for reasons already mentioned and you are going to be disappointed with their results. But I would like to see you construct a set of step headers. You will be pleased with what they can do for you...

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There's no such thing as too much cam....only not enough engine!

I have Clifford 1 3/4" long tubes on my race car. And I have an exact same set in 1 5/8". The only thing I would need to to do to test the theory is modify the back 2 tubes so they do not hit my Weber manifold. It would be an interesting test to see if it really is faster with the smaller tubes and no other changes.

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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

As long as you are constrained by the stock cylinder head, that's going to always be a limiting factor with the Slant....

Rick, you also mentioned in a previous post that your car isn't the most consistent from pass to pass, often 1 to 2 tenths difference, so I don't know that you could really perform a very valid test to prove or disprove a header swap based on its inconsistency that you mentioned. That's one way historically that some parts have gotten a bad rap due to the car being the cause of slower ET's and not the part itself....

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There's no such thing as too much cam....only not enough engine!

.1 in the 1/4 is a weather change at the track for most cars.

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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

You will have to likely do a fuel jet or emulsion tube change if you swap headers. A chassis dyno may give a more solid and exact result than at the track.

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There's no such thing as too much cam....only not enough engine!

I was not aware Clifford ever made 1.75" headers. Mostly they made 1.5" and I have seen some 1.625" headers on occasion but they are much less common.

Lou

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Home of Slant6-powered fun machines since 1988

Yes I think you are right Lou! My big tubes would be would be 1 5/8 not 1 3/4". Scratch everything I ever said!

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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

Back in the day (1970's anyway) Jack would help out serious racers. I was not a "big name" racer, but he did build me a set of 1 5/8 headers to try on my car. I never saw the 1 5/8's for the slant listed in his catalogs.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Gary Bruner had at least one set and I've seen perhaps 1-3 more.

Lou

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Home of Slant6-powered fun machines since 1988

I believe Ron had them on his Dart as well

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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

We could ask Gary his thoughts.

As far as the step header design, what do you plan for to make that happen?
Like what sizes tubes, where to place the step, collector sizing?

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Hyper_pak

Gary told me he was sure they helped his combo, which was pretty stout (high 7s in 1/8 and mid 12s in 1/4, NA on gas). Running 13s or slower? Probably 1.5" is just fine.

Lou

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Home of Slant6-powered fun machines since 1988