I will heartily disagree with Dan on the intake issue. That 2bbl Aussiespeed long runner is superb at low-mid range. It should be perfect on your truck if the carb is jetted right. Better than a 1bbl or BBD on a stock 2bbl intake. Yes, I have personal experience with that setup. I did not have fuel puddling or bad behavior at low temperatures, at least down to about 30 F. I did run the 500 2bbl, which works well on about any Slant (yes, I have run it on stockers and 11:1 race motors), but the 350 should be as good or better given the mild nature of your engine. That intake actually does NOT work well at high RPM and really shines from idle to about 4500 or 5000.

It would really help you to have higher compression and more head flow for your application, but it sounds like that will have to wait. I second Greg's comment about going to a 3.91 rear gear with those tall tires.

Lou

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Home of Slant6-powered fun machines since 1988

That is valid theory, but it's an error to latch onto one slice of theory and proceed as though it is the only thing happening, when in fact there are a whole lot of other effects happening at the same time, and they can be enough bigger to overwhelm/cancel out the one we've got in mind.

This isn't limited to intake manifold design; I run into this all the time in my professional field (vehicle lighting); people latch onto one little slice of operational theory ("LEDs light up at full intensity immediately power is applied, instead of taking a quarter-second like a filament!") and then draw incorrect conclusions by loading that one fact beyond its rated weight ("…and so it's a great idea to put 'LED bulbs' in my brake lights because then they'll be better and safer!") without knowing or understanding the many other factors that go into it, which make "LED bulbs" a bad, safety-degrading idea in many/most car lights meant for filament bulbs.

Back to intake manifold design: the resonant ramcharging effect you have in mind is slight and narrow (in terms of RPM range) when the whole engine is carefully configured and tuned for it as a system. Without that whole-system configuration and tuning, the effect is nonexistent at best.

Meanwhile, other stuff is going on: a great big plenum and large runners mean low velocity for any given engine speed, which means plenty of time and opportunity for the gasoline droplets to fall out of suspension and condense on the manifold walls, which are both large in area and cold (even with an improvised heater) because of gasoline's latent heat of evaporation. A fuel-air mix that might have been more or less correct when it came out the bottom of the carburetor is badly outta whack by the time it gets to the cylinders. Jumping around from too lean to too rich and back again, seldom near correct. This forces you to jet and tune the carburetor so the engine will run tolerably. It won't run well, and you'll be pouring gasoline money out the tailpipe, as well as down the sides of the pistons; it washes the oil off the cylinders on its way down to contaminate the oil in the crankcase, which greatly accelerates engine wear…and further screws up the mixture via the PCV.

The Hyper Pak, the intake from which was a major inspiration for the Hurricane piece, was very decidedly a high-RPM setup. A lot of that was due to the big camshaft, but you'd get crummy driveability and economy with that intake even with a reasonably small carburetor and a standard production cam.

In the '70s-'80s, Edelbrock put out a family of intake manifolds for V8 engines, specifically designed to improve fuel economy and low-RPM torque/driveability. They did this with small, well-heated plenums and long-as-possible runners with small cross-sectional area to keep the mixture velocity high and homogenous en route from carburetor to cylinders. Those intakes worked as promoted.

If there were a thing such as a well-heated Slant-6 intake with long, small runners and a small plenum, that would come a whole lot closer to doing what you have in mind—but there isn't, so you can't have everything on the want-list. "Long" has to be the thing to go away off the list, which is why [lather-rinse-repeat re stockish-type intake manifold].

None of this is to say I'm all the way right or Dart270 is all the way wrong. You will have to ponder all the advice you get and make the decision that's best for you.

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

Yes it would have been nice to cut the head and do some basic home porting. But maybe on round 2.

I ran that cam in my 85 D100 for 3 or 4 years. I had headers and a 500 Carter and automatic transmission, with 3.55 gears. I towed my steel deck trailer and race car on it several times. Probably close to 5000#. It towed Ok but mostly I was on pretty flat ground. Towing 2500# should be fine. I did have the luxury of Disc brakes up front and I installed "Big Car" rear brakes off of something. Maybe an Imperial? 11" X 3" I think. That helps with stopping. I also installed air shocks on it since it was only a D100 and they squat down quite a bit when loaded.

I would definitely run your intake and carb since you have them. They should work well. I also have never had any real trouble running the truck without carb heat. Yes it would probably be better, but we still get pretty could winters in PA, and I have driven mine year round without issue.

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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

One other note: you would profit (driveability, fuel economy) by using a thermostatic air cleaner setup. It would not be hard or expensive to put together from wrecking yard parts.

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

Seems like a fun build!

Agree with Dan that heated intake air can help, especially with the long runner intake. (in cold or cool weather)

Also if need be splitting/dividing the front and rear 3 cylinders may give better "TrucK" performance, if you decide you want more grunt in some future revision.

https://www.slantsix.org/forum/viewtopi ... e&start=15

Brakes are suspect at the moment - plan on putting in a new master cylinder but i may consider disc brakes since the current brakes are already problematic (very spongey). I'll look into the scarebird conversion kit.

Thanks to everyone for all the input - a lot of expertise that's helping me take out the guess work.

Thanks Dan - i'll look into this. Can't seem to find much online. If anyone comes across anything send it my way! Makes sense.

'70-up cars of pretty much all makes came with a thermostatic air cleaner. It is described in detail here. Get an air cleaner assembly from any kind of car/truck with that setup. The air cleaner has to be configured correctly to fit on your carburetor, which won't be hard; the Holley 350 2bbl takes the same diameter air cleaner mount as many 4bbl carbs used on production cars. Chrysler, GM, Ford, doesn't matter, just take note of what you get it from so you can easily buy appropriate air filters. You won't need a crankcase air inlet fitting on the side of the air cleaner housing on your '65 (on the other hand, ducting the crankcase air inlet this way is a fine idea that makes life more pleasant for you and for the engine, and hurts nothing). Make sure the air cleaner you get has a working snorkel damper door actuator, that's the flying-saucer lookin' thing perched atop the snorkel. Apply vacuum to it and see that it pulls the snorkel door into the up position and keeps it there until vacuum is released (you don't want vacuum to leak/bleed off).

The factory setup used a stamped sheetmetal "stove" fitted around the central collector area of the stock exhaust manifold. If you're using the two-new-castings type of DDs ("Dual Dutra Duals") this central collector area won't exist, so you'll need to fashion a stove of your own. Can probably do it without too much hassle by reworking a factory "stove" from a V6 engine of one kind or another. Take care to match up the diameter of the round fitting on the underside of the air cleaner snorkel with the one on the "stove". Then you'll need a flex duct to go between the "stove" and the air cleaner snorkel. They're readily and cheaply available in whichever of the common diameters you wind up with, and in a variety of lengths.

You may need a new air cleaner thermostat; they go bad after a few decades. I have a few new ones left; PM me when you get to that point.

Hookup is easy: manifold vacuum to one side of the air cleaner thermostat, other side of thermostat to snorkel actuator. If you want to get de luxe about it, there's a special check valve you can put in the vacuum hose from the thermostat to the snorkel to further improve cold-engine driveability.

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

Joe

I wasn’t planning on spending money on upgrading the brakes - but the more I’m reading the more I’m thinking it’s money well spent (particularly if I plan to tow regularly). Any guidance or alternatives please chime in!

Planned Disc Brake Conversion (very expensive - but can’t find scarebird kits)

https://www.ebay.com/itm/176486290018?m ... media=COPY

With my taller tires I have Minor Rub when steering wheel is fully turned rubbing only at the end of steering travel (left or right). I can either reduce travel by adjusting the spindle stops or put a lift kit on; open to other options. Which is the best? Below is a link to 2.5” Lift Kit. If I do this should I get steering stabilizer? Thoughts?

https://www.rockymountainsusp.com/lift- ... ?c=324&i=0


If anybody has better ideas and can provide links send them my way!

I have a '61 D100 with 225 and 3 speed manual. Back roads and gearing is the way to tow a moderate amount in these trucks. Light up like a Christmas tree and take your time in hilly country.

I was thinking of using a NP435 because of the granny gear. The Gear Vendors is available for the 435 at a ridiculous $3,500 new. The g/v show up forsale used - still spendy. A late model 5 speed manual is a better plan.

Until 1954 Dodge Job-rated trucks up to 1-ton used a 218 flathead six that was also used by Plymouth, then in the v8 era the related 230 was the standard motor. The trucks
used various gears and brake options. Back then virtually all roads were back roads.

Should of listened to Dan. Truck Runs very poorly in cold temps. Very Spongey accelerating in first gear/bogs down and dies unless i rev the hell out of the engine prior to disengaging the clutch. I'm thinking it could be my timing with the electronic ignition/or something with the vaccuum advance.

That's a damnuisance. It is absolutely not my intent to laff or go "toldjya so" or anything like that.

I do not think it'll be fixed with timing or ignition adjustments, but by all means check all of that carefully. If the truck runs well once everything is good and hot, though, I think you kinda have your answer staring you in the face like an ogre.

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

What temperature are you driving in now? Am I seeing headers on the truck? Can't tell for sure. You may be able to build a heat box around some of the header tubes to get some more heat into the intake. Play with the choke adjustment and the accelerator pump shop may help some. I run a 4 barrel and headers year round in PA winters with no real problems. Just give the truck a couple minutes to warm up and it is fine. Not like a new fuel injected car or truck, but still very drive-able. My headers wrap up pretty close to the underside of my intake too.

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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

Rick - in all fairness it’s pretty cold (15-25 degrees) when I drove it. We got heavy freezing rain with salt so I don’t plan on having it out for a while.

FYI - The electronic ignition I put in has an advanced street curve (Rick’s Mopars on EBay)

No headers - dual dutra dual exhaust manifolds to dual stainless exhaust. Holley 350 cfm carb has manual choke.

Oddly even after it warms up it performs poorly - which makes me think it’s a timing or vacuum advance issue? Does that make sense?

If the curve is too aggressive (advancing too much too early), it could lead to the poor low-end performance, hesitation/bogging, especially when I trying to accelerate from a stop.

If I don’t plan on driving it in winter months/extreme cold temps -

15 degrees is pretty cold! If you leave the choke on a little does it drive differently?
I doubt the curve is the real problem. Is it pinging badly? What is the initial advance and what is the total advance.
If total mechanical advance is limited to not more that 30-32 you should be fine. To much advance generally slows down our race cars at the the high rpm end of the spectrum, not the low end.

I would definitely check for air leaks at the intake and carb. Does changing the Accelerator pump shot help the bog/hesitation?

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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