Greetings. I am putting together a 1966 Dodge Coronet with an original 49k /6 motor/driveline and looking to put a HYPERPAK intake on it. I live in Farmingdale NY.

Thank you in advance.

Bill

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

What is your intended use for this vehicle? A hyper-pak is NOT an ideal intake manifold for a street driven vehicle. It can be made to work, but it isn't easy. I would think a vehicle driven in New York would benefit from the heated manifold provisions offerd by the stock one and two barrel intakes, as well as various aftermarket intakes like the Clifford or Offenhauser four barrel manifolds. For a big heavy car like a B body driven on the street I think a stock two barrel intake or an Offenhauser with a small four barrel carb (or two barrel on an adapter plate) whould be preferred.

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Casually looking for a Clifford hyperpak intake for cheap.

I plan on wreaking some mild havoc on the streets. would love to race it at some point but no track where I am but an old school race car feel is what I'm after with the Coronet.

Heated Plenum box from Aussie Speed under the manifold.

Hot snotty aggresive cam, lifters and valve springs once I can crack the code on which cam to use and why.

3 into 1 Headers (despite advice not to) with a y pipe (flowmaster 2.5 x 3 if there's no smaller one available) into a single 2.5" exhaust pipe into a FM40 out the back or turned down just before the rear (jury is still out). Maybe a Flowmaster HP2 as well just before the muffler as well. I'm concerned about the tinny sound and the harmonic drone at highway speeds.

Possibly a stall speed converter once I know what cam I'm going to use. May wait till I get the cam, head work, exhaust and intake setup first.

I just bought a Offenhauser 4 bbl manifold to get things off the ground but as I say, I really like the Hyperpak. It's badass!

Looking into the new FITech EFI system with the power adder module to richen the mix once the NOS kicks in. I see 100 shot kit seems to be safe as long as not abused. The FITech system has some nice features about it and really seems to smooth things out. Funds are not in place for that yet so, in the mean time, a suitable 4 bbl carb will have to suffice.

If and when I blow the rear I was looking at the Ford explorer 8.8 rear (1997-2001 I think). It's pretty stout and can be had for a couple hundred dollars, comes with 3.73 posi as well as disc brakes and is lighter, cheaper and stronger than the Mopar options.

That's where my head is right now. I'm still learning so let's see where I end up.

Thanks for your help in advance and your interest in my project.

Bill

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

Having been through this in a few variations, there are things to consider:

1) Even the Fitech is a throttle body EFI so you will have all the problems the carb version will have.... you will have to work out the issues of being about 20% richer when cold and lean back out when warm...( I would suggest getting a book on carbs to understand the fundamentals on how they work and what each circuit does... as you will need to retune the carb to work with the manifold, then apply it to the TBI programming)...

2) Using water heated manifold heat will make things hard to work with during the months that the ambient temperature is under 40 degrees.... I used an exhaust heated plenum to use it year around... but cold hard starts and very rich mixes aren't uncommon (and can wash down the cylinders an decrease your bore life).

3) The long rams will help with torque in the heavy car, but you will need to help the engine and run a combination of better rear gears and an overdrive if you are going to street drive it(.... you will want to split the plenum if you are wanting to shift the powerband from 4000 rpm+ to something closer to 3000 rpm +)

This type of cam will make the car a trailer queen and not drive to the strip (a 360 will pass you at the pump with the carb to match the compression, cam, and rear ratio, expect drone since your highway rpm will be in the 2200-2500 rpm range if everything is matched right)....

Stock lifters are fine for the 250@.050 .500+ lift cams... V-8 valve springs with dampers and O/S valves will be wanted and the guides turned down to match the lift...along with an overbore to unshroud the valves for best flow.

You will also be spending a lot of time porting the runners in the head.

On top of all that, you will need EI and a fully recurved distributor to make the best use of the modifications.

-D.Idiot

I guess the Dutra Duals allow for better heat passage from the exhaust manifold to the intake manifold? I thought the hot water plenum heater would work just as well once it was warm. FITech refers to the car starting like a newer car once it learns the car. It also has sensors to gauge how it's running. Is that not enough for the slants?

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

How does one go about splitting the plenum?

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

How well will the car run with the stock 2:93 rear? I know this motor is supposed to be very torquey when properly setup. Is it torquey enough to overcome the low gearing?

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

BTW, right now I have an Offenhauser 4 bbl manifold with the stove pot bottom. Anyway to rig heat from the headers to the stove pot under the manifold?

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

Truth be told, I really think the triple Webers are very trick. Not sure how they'd be on the street and how well they'd keep their tune but they sure are the hot blingy ticket!

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

Nope. The combination you are planning will need a really loose converter and at least a 3.91 gear to get out of it's own way. The HP manifold was designed to work with a stick, a lot of gear, and a fairly light car.

Unfortunately, the Hyper Pak is a lot more legend than good working intake.

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Official Cookie and Mater Tormentor.

by loose converter do you mean 2500-3000 rpm stall or higher than that?

Would 3:73 suffice? I'm looking at an explorer 8.8 rear for the weight savings, cost, disc brakes and posi included and the width is spot on.

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

I guess I'll run the Offenhauser for now

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

That's the operant language... "once it was warm"... you'll have about 5 minutes of in driveway idle to get it warm to start making a difference... the manifold is a lot of metal to heat up as well... hence the reason I went to exhaust heat... it also may not all fit under the hood without a lot of modification to the air cleaner...
I marked the manifold to determine the middle of the plenum and lined up the runner divider between runners 3/4.. and cut it up to that point with a large grinder cutoff wheel... then made a divider out of .040 T-6061 aluminum (shop scrap...side benefit of being a sheet metal worker)... mocked it up, and had a welder fillet the cut and divider in place.
Should be questions to ask in another forum before getting here...
Truth be told the slant is torquey... but stock for stock in the apples to apples, rpm band a 318 2 barrel will have about 20% more torque on it by the numbers.... to get the slant to properly motivate a heavy vehicle it needs to be geared so the ratio is kinder to move the car... this will also limit your top end, raise the cruise rpm and lower the mpg... (thus the desire for an overdrive gear to put the kinder drag ratio 1-3 gears in check and have a final gear ratio to cruise with similar to the stock final drive ratio)... I had run the numbers if I ever got a 1970 E-body slant six... and I would be looking at an A-833OD truck transmission, or an A-500 and a set of 3.91's out back as 'zilla stated... this would be similar in weight to your vehicles and size is somewhat similar....but a well built small block or big block will out perform at the track... a well thought out street/strip build might also get acceptable track performance and mpg....

Literally to say... when backward engineering my drag numbers to something real world in quantity... if the stock 1 barrel engine was rated at 215 lb/ft of torque... going "all out" in my heavy car with a FatPak and headers... I only have improved that peak number about 70-80ft/lbs in the tighter rpm band... yet my HP numbers are about double the stock numbers ... (for mpg you will work to maximize torque, HP is just top end, or the ability of the engine to do the work up to the max rpm)...

More 'fun, could be had overall if you went with boost....
Weld up a 16 gauge box to bolt up to the bottom of the stove, drill 2 opposing header runners so heat/exhaust pulses will pass through the box and plumb them in (a threaded bung and some EGR flex tubing from a junkyard will work...I got mine from an early 80's pontiac)... runners to drill will equal 7... I used 2 and 5 since they were the middle of the "set" instead of 3 and 4 or 1 and 6 (thank goodness for even fire engines...)

This is true, but you will learn a lot about manifold design, gearing, carb set up, engine builds, etc.. if you do decide to set this up (or a triple webber or 6 mikuni's, dual webber, etc..)... just don't expect it to run like a champ out of the box....

For your first "step"... since you have an offy... I would upgrade the engine as follows for best torque and driveability:

Pull head off engine and measure the piston top at TDC and the CC of the head... post and allow us to help you figure out what to mill to get 9-9.2:1 SCR and about 7.8-8:1 DCR... you can keep the stock springs if they are uniform in pressure and within their factory specs

Find a buddy with a large air compressor, a die grinder, and a bunch of burrs long and short shank, and get rid of the factory casting flash in the ports, smooth the transition from from the runner to the valve bowl, and smooth around the valve guide casting... don't go hog wild in there... for street you are going to keep the port smaller so the velocity stays high at lower rpm... when you have driven this build and are ready to go a lot more wild we will talk about opening the runner more... get a spare head to work on in the meantime so you can swap it on later....

Swap cam to the RV10 cam and degree per recommendation from above milling and DCR....

Swap gearing to 3.23's...

Use an Edelbrock AVS 500 cfm for best plug and play use...you may need to change the metering rods... if you decide the Holley 8007 is going to be you choice... get the Emmanuel book on tuning holleys and read front to back.. set it up for a secondary metering block with #53 jets and a quick change secondary spring pod (purple spring to start), and mopar throttle lever stud...

You will also need to go to a Lokar or Bouchillon Cable kickdown linkage (have in hand before the swap over...)

You can use the stock manifold and heat riser and a 2 1/4" ID exhaust pipe for now... if you go headers... going to dual 2" pipes (one will have to 'tuck under' the rear hump in the oil pan). will work fine... they will also work if you upgrade to 10:1 SCR and more cam/convertor later... be warned that the header flanges may be 1/2" and the offy flanges 3/8"...you may be able to torque to yield using a remflex gasket, but it will only be used once and need to be replaced if something isn't right...

If done right this will be a good improvement over stock... then you will know where you want to go for the next 'step' if still desiring an exotic underhood manifold...


2 cents-

-D.Idiot

Thank you very much for your input. I really do appreciate it. How do I switch this over to another area so as no not to muck things up. I'm new to the site and I'm not quite up on procedures and protocols yet. I'm sorry for the inconvenience.

Bill

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1966 Dodge Coronet Deluxe 2dr sedan
1966 Plymouth Belvedere II 2dr hdtp
Both slant 6 cars

I will move it to the Engine section.

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Official Cookie and Mater Tormentor.