My Hpak manifold is ready to install, the plenum is split and the surfaces machined....

Here are a couple of pics of the plenum showing the divider and the equalization hole, and one showing a plate mocked to to see if the throttle plates would hit the divider....










I have an assortment of throttle cable to choose from all cost about $5 each at the local pick-a-part...the one I'll use is the short one at the bottom, it's from a 2.2L Dodge 600 and it has the same ends as a stock cable, but it's much longer. The other two in the picture are one from an LHS in the middle, and the top one is from a Dodge Caravan, but they would need some 'tweaking' mount properly.





I mocked everything up on my spare block and head to make sure it will work, I used an old intake gasket I had lying around so I could work out any kinks that might occur along the way.




Tomorrow morning, I'll be working some ideas and plans over with a friend, and hopefully I'll have the brace, throttle cable bracket and return spring bracket ready to bolt on. I'll also discuss with him welding up a pair of temp pipes, to go on my dutra duals, so I can test and tune it, and get it over to the exhaust shop without burning up the rubber in my spool mounts....


Things I did notice:
Getting the triangular washers on wasn't as hard as I thought, but getting enough 1/4" extensions together to fit under the Hpak was a real test of dexterity. Seemed to work well, hanging the duals by the outside studs first, then hanging the pak by the central stud, then placing all the washers and nuts on and torquing in the proper sequence. I also will have to reroute the fuel line, since the stock super six one comes a bit too close to the front dutra for my liking.

Tomorrow as time allows I'll mock it up again with all the trimmings attached and take some pics for those thinking about doing the 'Pak'.
I have eveything almost set, I have to remove my super six set and replace the 'sandwich' anyway, so now is a good time to do the swap and see how much fun it will be, before the bad weather sets in (if it becomes a real 'tinkertoy' I can always swap back to the super six with dutra duals too... and play with it more another day....)

Here We Go!

-DusterIdiot

HeyDI, I started mocking mine up today and its going pretty good and I also have some ideas on a bracket and heat for the plenum.Just out of curiosity what dipstick are you using ?I t looks real craamped around that area.
Slanted Attitude

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Ive got a slanted attitude and a heavy right foot.

What's the purpose of splitting the plenum in the manifold?

And would a Hyperpak manifold give any performance gain with an EFI slant?

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

The split plenum helps the low rpm mixture volocity and distribution.
I had a bit of a bog with an open plenum H. Pak, that went away when I divided the plenum.

Great job on the divider DI, that should do the trick.
DD

Being in construction, I have a pile of 'unistrut, and I finshed welding up a HD bracket for the bottom of the PAK and a cable holder. (I need the heavy duty ones, speed bumps don't stop me or my car, and I'm sure I'll knock this thing against the driver's side fender if I don't get it braced good.)

I have the long dipstick, and I see no problems with routing the duals, and where the stick is since I have a roomy engine bay, and a 225.


Jopapa, go back and look at some of Doc's postings about the Hpak and EFI....once I get this setup, next years project will be to get a Holley Commander 950-650 cfm TBI kit and replace the carb with something I can finely tune while driving, and change the settings from street to strip.


Splitting the plenum should help me tune the carb as is I had 1 progressive two barrel carb for a set of 3 cylinders (easier to get the mixture right). For street purposes it helps with idle quality, vaccuum signal to the carb, throttle response. The hole helps correct any left to right mixture distribution problems. I notice that the plenum is very irregular and when divided the rear bank(456) has less plenum volume that the front bank(123). If you've ever had the priviledge of riding with a guy who's proud to put a single plane manifold on his big or small block, dump a big carb on it and watch his face while it tries to idle or bogs of the line but runs awesome once the tach leaves the 4K range or the guy has it buried in the 80-90mph range you'll know what I'm thinking.

-D.Idiot

Slanted, take lots of pics of your assembly process, take notes, since we're kind of the first set to get these for regular daily driver use, we should get together with Doc and set up an article for the board, so others buying them know what they need to do to get them to work. I'd be game, if you are!

I layed out the divider (simple pattern job I do when I'm at a Shop job), the Welding was done using 4140 by Wade Skinner in Junction City,OR...his shop is 'The Western Art Gallery' (he makes custom signs for ranches,etc...but he also does other work, and has been welding for over 48 years...).


Here's my 'crude' mock up for a HD brace, and throttle assembly. I wanted to make sure it was 'modular' so if any changes occur I can bolt things on, displace items, or cut and reweld it....



I cut the unistrut channel so I could bolt it to the side of the hpak plenum, and welded a 'stabilizer plate' to the bottom to attach to the 'brace stud'. The throttle cable is from a Dodge '600' and it's perfect, the unstrut at the back is my simulated 'firewall' opening, which should work very cleanly.





The throttle cable bracket bolted to the unistrut is the stock Dodge 600 bracket off the front of the motor, find the right height and bolt it the the unistrut, easy!!!




Here's a completed look with the spring tower in place. I'm going to leave it as-is, since it will also have to serve as a bracket holder for the fuel line to the Holley....

The Brace is very simple, getting the angle and offset are not easy though, I have to tweak mine a smidge. and I want it to be sturdy. My measurements indicate that the end of the Hpak in my bay will be 1 1/2" from the wiper fluid reservoir, and be a few inches above the driver's side shock tower.







A birds eye view shows that I can leave my dipstick tube bolted to the rear manifold and still access the handle from the to of the manifold, another option will be acquiring the longer yet truck dipstick and tube.




I've also mocked up two flanges that I'll weld up some pipe rems to so I can dump the exhaust out side the bay temporarily while I play with things, if it all works right, then I can take it to the exhaust shop without calling my buddy for a 'tow'...




I think the front dutra could have enough vertical pipe to run it below the plenum for some 'radiant' carb heat, rather than running a pipe to the manifold floor. I'm feeling that I may do it that way rather than permanently heating the intake. If it still gets cranky in December, I've been doing the Mopar 2 foot-3pedal shuffle now for over 18 years...it's a great dance, even on steep hills!


I'll take a break tomorrow, the weather was a bit salty today, have some 'family' business to take care of. If my son goes down for his afternoon nap, the super six stack will be coming off, and Thursday morning the 'Dawn of the Hpak' should start. (Sounds like a Z-grade movie where a bunch of possessed junkyard cars roam the countryside killing people in search of Octane...)


Hey, Doc! If you can think of anything we should look forward to while putting everything together let us know! I'm pulling a 'just-in-case' item and using a Mr. Gasket 320 to put my set on, the Fel-Pro set is great for normal use, but the extra 'squish' looks like it'll keep things sealed better.

-D.Idiot

looks verry nice. Bruce J.

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78b4ramSnortbed/6

Will the standard clifford manifold work with dutra duals?

If not, what is the solution? thx, raydart

I can make Dutra Duals work with just about anything.
The question I have is if your Clifford has any heat riser boss on the bottom of the manifold?
DD

Hey thanks Bruce, and thanks for 'kicking my A$$' into gear to start this, otherwise it'd be like my set of 198 rods that sit in a box under the bench dreaming of a day to be installed into the 'mockup' block....



-D.Idiot

"Brrrmmmm...Brrrmmmm...Brmmm"-the sound that Idiot Jr. makes while sitting behind the wheel of either of my dusters....and he's almost two...13 years to go.

DI,Iwas thinking the same thing on running the front pipe from the DutraDual under my plenum but seriously thinking on using a flexable street rod style dipstick.I plan on doing somemore grinding tonite on my manifolds to improve fit and to get the triangle washers to fit better.BTW,Im taking plenty of pics and I do plan on this being a true 3 season daily driver .Good luck and keep us posted.
Slanted Attitude

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Ive got a slanted attitude and a heavy right foot.

It's a black 45-4500. I haven't seen it but I can cancel the deal if it will not work for me. So I need to know what my options are.

Maybe I would be better off with offenhauser.

what sucks is I bought 40 idf webers just b4 clifford stopped endorsing them. thx mang

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Mopar or Nocar But my wife drives GM

Keep me up to date on your progress too...I'm ready to plug my stack. Weather looks good, and I should be able to give it a 'college try' tomorrow morning.


I used a regular rough wheel to 'dog out' the area for the triangles and round washers. To narrow the runners, I used one of the discs that has some really rough sandpaper wedges overlapped (I mean the welding shop gave me a nice 20 grit aggressive disc). It doesn't take long for it to whittle things down with it, and since it's not a normal grinding disc it doesn't clog up with aluminum taffy....


more to come, stay tuned.

-D.Idiot

Looks great DI!

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Official Cookie and Mater Tormentor.

So this is on the road now as a daily driver?

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick