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manifold for the raised block Desoto Hemi

Discussion in 'The Hokey Ass Message Board' started by 38 mopar_fan, Oct 28, 2007.

  1. TR Waters
    Joined: Nov 18, 2006
    Posts: 1,439

    TR Waters
    Member
    from Vermont
    1. Early Hemi Tech

    Pick any of the following: COOL. WOW. AWESOME. And thats just the beginning.

    I just received one of Peter's Desoto raised block intakes for review. Let me say straight up..... you guys are going to be VERY pleased. This intake is a first class part....from design to casting.

    Design
    1: Peter took the time to incorporate the thermostat housing as well as a bypass hose port. This in itself will save everyone a ton of time and money trying to get the water in and out.

    2: Interchangable tops are nothing new, but Peter took the time and effort to make them available for his intake. The 3 tops available should satisfy anyones needs. If not, its quite easy to design your own top plate.

    3: I dont know how to classify the height of this intake, other than "just right". It has raised runners, but should still fit under most hoods without problems.

    Casting
    1: Top notch mold and casting. This is NOT an amateur undertaking. The base weighs approximately 11 pounds. The casting is equal to, or exceeds any cast intake on the market. Period.

    Please feel free to ask questions. I'll try to answer about the intake the best that I can. I am sure Peter will correct me if I am mistaken.

    Peter will keep you updated as to "WHEN" and "HOW MUCH".

    I will have this intake at my Carlisle booth in July. Those attending will see first hand what a great job Peter has done.
     
  2. Stan
    Joined: Oct 26, 2007
    Posts: 54

    Stan
    Member
    from UK

    Well thats what I call a ringing endorsement.

    As soon as you're ready to ship Peter just let me know.
     

  3. Same for me
     
  4. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Thanks guys, just spent a full day in on the dyno. Some interesting numbers and surprised the guys with how the manifold performed. Anyway I’m smiling but just off to find some more jets or run some drills through the ones I have. Going to tune it better and see what we can get out of it in the morning.
    ]Got heaps of video and printouts to load so this is just a quick update as I walked past the computer

    Cheers

    Peter
     
  5. ward3162
    Joined: Sep 11, 2006
    Posts: 40

    ward3162
    Member

    Peter

    Very impressive. "Streetability" is my only concern with taller intakes. Can't wait to see dyno numbers. TR Waters endorsement carries a lot of weight. Any idea on cost yet?
     
  6. Stan
    Joined: Oct 26, 2007
    Posts: 54

    Stan
    Member
    from UK

    Peter

    I know it might be a silly question as I know we talked about using 97's, but the 3 twos top has 3 bolt fixings doesn't it?

    Its just that I'm trying to source some 94's and don't want to have to trade them in for Rochesters!!!
     
  7. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Well people after some thrashing on the dyno I can say that its difficult to get the smile off my face.:)
    Given the opportunity to run the engine for a day and a half was an amazing experience. Standing next to the fresh engine topping out at over 500revs worrying if I had assembled it correctly soon turned to yeah its going to hold together what can we get out of it and lets do that again.
    My only disappointment was going into these runs with second-hand carbs. New carbs would have taken one level of uncertainty out of the equation
    First thing was running on the two barrel manifold with a carter off a 318. This pulled to 190 HP but went lean at the top end. I made the call to stop messing with the two barrel and get the original four barrel manifold with a carter 600 cfm on. After some sorting runs we got 251 HP and319 lbft flywheel torque.
    The first image is the HP curve first runs we did with the stock manifold and then my manifold
    Please note this is at the diff without correction for loss. Given the loss figure the best pull was 251 HP with the stock manifold.
    Red - first with stock manifold and 600cfm carter
    Green – Same with jet change
    Dark blue - Same with jet change you can see the changes in the jets
    Pink – First pull with single 600cfm on my manifold
    Light Blue – Next pull with bigger primary jets this was a big improvement but top end down a little
    Yellow Swapped the top, two 600cfm fours with same jets Very happy
    The yellow peaked at 255.6HP but look at those curves
    The next image is the torque curve for the same runs. Note the light blue and yellow is looking as good as the HP curve. You can see the torque curve drop as the carb goes lean
    Given the problem with leaning out I needed bigger jets than the spare ones I had. I couldn’t get carter jets locally so picked up some drills and set about drilling jets to get what I needed
    This morning I reverted back to the single four top on the manifold and played with the jets. The third image is the graph of the last run. WE got 268.7 HP at the flywheel corrected for the loss through the diff. and 315 lbft flywheel torque. As you can see both are good strong curves. We could have spent more time fine-tuning to get the Lambda (air, fuel ratio) better. We started out with a lean out at about 3500 rpm. Fixed that but then it was slightly rich right across the board. Worked out how to fix that but time was against me doing any more.
    I would like to thank the guys at Waikato Institute of Technology, very helpful I didn’t get to operate the throttle for the runs, I got to warm it up and do the spanner work and take some excellent advice. They got a group of students in and we gave them a demo run and am impromptu lesion on manifold design
    In conclusion, was this worth the effort, in a word yes! We could have got a whole lot more scientific in our approach but a single 600cfm on my manifold got approximately 7% improvement. The fact is it pulled hard across the rev range and didn’t appear to falter. Driving could be a totally different result. It could have an annoying flat spot or some other nasty behaviour.
    Testing the headers with a thermometer showed good fuel distribution without the front or back cylinders starving
    The other good thing was the heat in the manifold. With the water warming the floor of the plenum fuel separation should not be an issue. Should be good in the colder climates
    Video and photos to come.
    Cheers
    Peter
     

    Attached Files:

  8. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Hi Stan,
    Never any silly questions mate
    The 3x2 base has pad size and spacing to suit Rochester carbs they are a four bolt, the issues comes that they are available in two bolt pattern sizes. I have access to six later model carbs with the big spacing’s
    I send a 3x2 up to Tom without the carb drilling (blank) but I have drilled one for the 3 bolt pattern of the 97’s
    I believe the early Rochester carbs have the same spacing as the two bolts on the 97’s but that could be wrong.
    It is my intention to drill them to the customers requirements. Ultamitly I will have a selection of predrilled plates.
    Will get that photo for you to see what I’m talking about. Anybody confirm the early Rochester bolt pattern?
    Cheers
    Peter
     
  9. Mopar Mama
    Joined: Nov 19, 2007
    Posts: 234

    Mopar Mama
    Member
    from Boise, ID

    I saw this and peed my pants! :eek: As for Peter's intake, sir you rock my world! Too bad I've got nothing to put one one, otherwise yeah, I'd buy that!
     
  10. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member


    Hi, dyno numbers posted, “Streetability” is something that will come out of discovery phase, The best we could do was some slow throttle pulls and dold it steady on the throttle and vary the load. It looked ok but only driving some street miles will tell.
    Cam and compression ratio will change things also. They dyno was logging down to 1 rev changes so pages upon pages of data logged.
    As this is a bolt to the wheel dyno it does not have the inertia of the rolling road type dyno where the rollers will smooth out power. Some of the spikes would not have shown up on the rolling road or possibly in a driving situation.
    Unfortunately I don’t have access to an engine dyno so this was the best available. I believe the NASCAR guys use these dynos for their tuning.
    Feel free to ask questions
    As to the dreaded cost, Its working out at $675.00 USD Have been trying to keep to the original 650 I talked about but material costs etc have been climbing. That will be for one manifold and one top plate. Additional top plates are available at $100 USD. That will include a top plate gasket and the necessary bolts to hold it down.
    The thermostat housing is sized to take a standard Chev thermostat and housing. On the development model I got a swivel neck housing that worked perfectly. I figured they are cheep and readily availble


    Cheers
    Peter
     
  11. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member


    Nice to know I rock someone’s world:)
    Got to love them mopar people
    Cheers
    Peter
     
  12. Stan
    Joined: Oct 26, 2007
    Posts: 54

    Stan
    Member
    from UK

    Well let me be one of the first to congratulate you Peter, you must be very happy with the results. The dyno data makes impressive reading, but as you say, need to get some on the street to see how things really are!

    Stan

    Have also PM'd you Peter
     
  13. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Thanks Stan, I am very happy with the results. Just waiting for my son to upload some video of the dtno runs to the pc so I can load them. He borrowed his mates video camera and was in charge of recording the event.
    I have been struggling with what box to run behind the Hemi, auto or manual but after listing to the open headers with the motor running through a diff only I figure I have only one option. Got to find a good manual box.
    Cheers
    Peter
     
  14. Stan
    Joined: Oct 26, 2007
    Posts: 54

    Stan
    Member
    from UK

    Mine came with a 350 already on the back so I'll go with that, altho' I think a manual would be the better option. I'd be interested to know what you come up with for a box and conversion.
     
  15. ward3162
    Joined: Sep 11, 2006
    Posts: 40

    ward3162
    Member

    Gentlemen,

    Don't want to get off the subject of the intakes........However, I'm in the process of a 341 build and I'm going to but a ford toploader behind mine. My friend (Mechinist) says it shouldn't be that hard as the small block Mopar bellhousing( 360) is almost an exact match. A little flywheel work (10.5"/130 tooth) and a hydraulic release bearing are needed. May have to cut and index the bellhousing to make the engine/trans spacing correct have to wait and see. If your building anything other than stock 341 you want a trans that can take the torque. Toploaders are almost indestructable. Just my 2 cents.
     
  16. captainjunk#2
    Joined: Mar 13, 2008
    Posts: 4,330

    captainjunk#2
    Member

    hey this is a cool thread i was curious has this manifold completed being tested ?
     
  17. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    No problem, the options for a box for me will be cost and availability. A tremec could be a good option but will need to do some searching on the net. They are available down her but range in price from 3.5 to 4thousand dollars. I have seen some second hand boxes imported down here for less that $2000. but they are an unknown quantity.
    I have a 904 auto that is an easy job to fit but would love a five speed box.

    Cheers

    Peter
     
  18. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Hi,
    It has been through the first dyno tests and I’m happy with the results to date, the next trick will be to pull the cam and get a decent grind on it and see what I can get out of it.
    I would love to go back and re run the tests with new jets, we finally got the mid range sorted but went a little rich across the range.
    After focusing in the single four I would love to re run the two fours and see if we could improve those figures. I didn’t run it on the three twos because the carbs I have need extensive rebuilding I could have spent a week alone getting them sorted and I didn’t have that much time available to me. A day and a half went quickly and for that time I was extremely grateful
    The amazing thing was the total different sound the motor picked up with the manifold on. The idle was better. From the collective knowledge in the dyno room we put it down to the straighter ports The peak power curve was better and that could be down to better flow than the original manifold design. I’m amazed they designed such a nice port in and out of the head and then stuck such a flat manifold on with tight turns into the head.
    Anyway finally got some photos to load up.
    The first is setting the motor up into the Dyno, At this point the motor has the stock two barrel.
    The next is John the Automotive tutor at the throttle on a full run
    Then John Giving the idle a fine tune to get it running sweet under the watchful eyes of a bunch of students keen to find out about this thing roaring its lungs out
    The last photo is an impromptu lesion on manifold design and what the hell is a Hemi. You have to remember most of these young guys had never seen a early hemi and appeared somewhat shell shocked to find out the thing was built in 56. Was a neat experience to talk about the roots of the Hemi and its impact on the performance world.
    As for testing finished “yes and no” would like to refine it and cam the motor raise the compression ratio and do some flow work on the heads. But I’m more than happy with the fundamental design. Need to get them out on the street and see how they drive.
     

    Attached Files:

  19. henryj429
    Joined: Jan 18, 2007
    Posts: 1,050

    henryj429
    Member

    Any chance you can post power and torque curves?
     
  20. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Hi Have a look on page 8 and you will see the power and torque curves I posted. I assume this is what you are looking for I have attached the last one again for your info. Let me know if this is what you wanted.
    Cheers
    Peter
     

    Attached Files:

  21. 33mopower
    Joined: May 18, 2008
    Posts: 243

    33mopower
    Member

    How do you plan on accepting payment?
     
  22. keithc
    Joined: Jun 3, 2008
    Posts: 11

    keithc
    Member

    Looks great! Will it fit a 291?
     
  23. 73RR
    Joined: Jan 29, 2007
    Posts: 6,227

    73RR
    Member

    Peter, you may not like the way a 904 mounts to the block. The starter sits about ½" higher than on a 727 which then hits the block. The peanut starters are the same.

    Your manifold project is a gift from the gods, and many of us thank you for making it happen. Keep up the great work!!!
     
  24. dashaquaddog
    Joined: Jun 22, 2008
    Posts: 2

    dashaquaddog
    Member
    from brisbane

    hi peter
    come in at this end of your advenger im in brisbane i like the manifold i have a 341 in my 36 dodge i would like to buy one 2x4 can you email me your contact.......?
    regards dale
     
  25. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Hi
    Can accept electronic funds transfer, Western Union, Paypal and international money order.
    Cheers
    Peter
     
  26. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Thanks for that, hopefully some of you guys will get a chance to see the Tom Waters will have on display one at Carlisle
    Unfortunately it will not fit the 291 low block but working on modifying one to fit. Don’t know if It will be that easy but will let know what happens.
    Cheers
    Peter
     
  27. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Hi thanks for that, hadn’t done any measuring yet just had the 904 sitting in the garage behind a 318 and figured that would be what I use. Will look at finding a smallblock 727. spent the weekend machining up two manifolds and talking through manual box options.
    Going to think outside the box to solve this one. One good option is for me to find a Australian turbo 6 Falcon or Holden Commodore manual box and adapt that. Will be interested in any advice or options
    Cheers
    Peter
     
  28. Benzine440
    Joined: Aug 30, 2004
    Posts: 3,276

    Benzine440
    Member

    I've got a small block 727 if you are interested.
     
  29. 38 mopar_fan
    Joined: Sep 10, 2006
    Posts: 223

    38 mopar_fan
    Member

    Thanks for the offer, always interested but would need to workout the shipping cost first. Probably worth me looking local first. What is the story on the box? Do you have a converter with it?
    How fast do you want to move it? Would need to arrange for someone to bring it back for me and sometimes that can take some time sorting out

    Will send you a PM
    Thanks again
    Cheers
    Peter
     
  30. keithc
    Joined: Jun 3, 2008
    Posts: 11

    keithc
    Member

    Thanks for the feedback on the 291 fit. Just what I expected. That would be great if you could get a fit to the low deck as well, I think there are alot more low decks than high deck DeSotos on the street in this part of the country.

    Thanks, Keith
     

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