EQ Heads and stock rocker arms?

Magnum Engine Swaps

  1. 1969GTS340

    1969GTS340 FABO Gold Member FABO Gold Member

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    AJ - Thank you for the assessment. I feel better about not having to swap out the 1110 springs if I run the 1.6 rockers. I am also running a 7qt pan with HV pump and the correct oil through push rods for the mag style head. The TF is going into a local transmission performance builder for a check up and maybe I should discuss gear ratio changes to better match my needs? This same shop will be building the converter once I have closer weight and engine performance numbers to lay down. The slicks are also 28's so overall our two builds sound quite similar and it's reassuring to know you have proven results to go by. When this portion of the build is complete I'll turn my focus to the suspension where I expect to find improvements for the <1.7 60ft times. Have you ever run this same combination in a 1/4 mile?e,
     
  2. AJ/FormS

    AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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    I recommend to leave the 727 ratios alone.
    Your starter gear is 4.88 x 2.45=11.96.The TC is gonna throw a multiplier into the mix as well for the first car-length.The slicks are gonna have a tuff time.
    I only ever took that combo to the track once; it was my DD at the time, so it was running full street suspension, hence the 2.2 60fts.. It did have BFG 325/50-15 DRs on it tho, for all the good it did.They were still spinning at 80 mph. Here's the thing, I run an A833 with a GVOD split shifting, so my powerband requirement is just a tic under 1300 rpm. So my combo is putting down almost 100% of it's power-peak for almost the whole run, to make about the highest average put-down, that is possible. Of the four runs (T&T) I made that day, only one was completed. I drove it there with my street tune, ran it, got a run, spent the day in the bleachers with my 20yr old son, and then we drove home.
    This transmission has ratios to run anything;
    You will not be able to run the qtr with 4.88s, you will be outta Rs. 5800 is likely to be close to an ideal trap rpm for that cam. If you manage 93 say in the 1/8th, this translates to about 118 in the qtr. To hit that at 5800 with 28s will take about 4.10s at zero slip . Round down to get 3.91. Those will get you 118@5813@5% slip, the 4.10s would be 6100.
    To run both qtr and 1/8 with the same trans ideally, requires a split of about 93/118= a .79 split and 4 gears; 3 for the Eighth, and 4 for the Qtr. And a sacrifice starter gear. For instance; running the 118 with 4.10s and a manual trans with a direct 4th will get you 5800. Running the Eighth at 93 with 4.10s and 1/.79 third gear will get you 5792. The A833 low gear is 2.66, so the starter is 2.66 x 4.1 =10.91 not very favorable. But there is an A833 version with a 3.09 low that is favorable, making a starter of 12.67; That's what I run. There is no A833 with a 1/.79= 1.266 third gear, so i run the A833od and a GVOD. The ratio I used was second over. 1.67 x .78 = 1.30,close enough. But I split the 1-2 as well, so that got me 4 ratios in the 1/8th,namely;3.09-2.41-1.67-1.30, BadaBoom.
    My mistake was using 4.88s instead of 4.10s. I severely underestimated how much P/W I had. So I had to shift one more time, into direct,lol. The tach was stuck on 7000 for all but the first 60 ft, where I babied it out, cuz those DRs couldn't handle 4.88 x 3.09 =15.08! DOH!

    If you haven't already bought the cam IMA thinking one size bigger and a wider LSA, something like the Mopar P4120653 which is a 284/284/112 with lifts of .528@1.5. This is a solid FT. I think this cam .050s at 240ish.
    My ducks were kindof all in a row; 367 cubes, 10.9Scr,.035 Q, 276/286/110 cam, very-close ratio manual trans,etc. The difference between your 350 and my 367 is only 17 cubes. But your powerband requirement is 2000 to my 1300. So all in all, it would seem that your engine would need a bit more cam, or more heads than my OOTB Eddies.
    IDK, like I said I only ever tracked that DD-combo the one time.........she mighta had more in her.
    I tell you what tho; the old DC bulletin book lists that .528 cam as a requirement for an 11.5 bracket racer with a 340/360 and X-heads. So 11.5 is about 116 with SS suspension, and 11.5 is about 414hp @3400#, so take that as you wish.
    I've never run that 284/112/528lift cam, but I did run the 292/108/508lift cam. At 1.6 rockers, that was .541lift. I'll tell you, that was an animal after 5500. IIRC I measured it at 249@.050. It was too much for me in my DD. The 108LSA is well-suited to a 4 speed.

    You might like this one, it seems a natural. It's a mechanical tho.
    "The Lunati Drag Race Cams are available for a wide range of racing applications from Sportsman to Pro. These camshafts produce unmatched torque for launching the vehicle off the starting line and maximum horsepower for a strong finish. Custom grinds are also available.Solid Flat Tappet. Good cam for high performance street or bracket racing in 340-360 cubic inch motors. Needs 3500 RPM stall converter, headers, 10:1 compression ratio and 4.10 gearing. Rough idle."

    • Advertised Duration (Int/Exh): 278/278
    • Duration @ .050 (Int/Exh): 251/251
    • Gross Valve Lift (Int/Exh): .570/.570
    • LSA/ICL: 105/99
    • Valve Lash (Int/Exh): .016/.016
    • RPM Range: 3000-7000
    • Includes: Cam Only
    Part Number: 30200912
    Previous Part Number: 404A2LUN

    I wouldn't call it an automatic cam!, but the lobes are incredibly fast, so it will make a lotta power with a minimal lope. It might look like this;

    Static compression ratio of 10:1.
    Effective stroke is 2.70 inches.
    Your dynamic compression ratio is 8.33:1 .
    Your dynamic cranking pressure is 168.48 PSI.
    V/P (Volume to Pressure Index) is 144...............................144VP,excellent

    But if you already have the 704, it's no slouch either. And one thing I like about the 704 is the split-pattern. It has enough exhaust duration that you can move it around some.
    • Advertised Duration (Int/Exh): 276/284
    • Duration @ .050 (Int/Exh): 234/242
    • Gross Valve Lift (Int/Exh): .513/.533
    • LSA/ICL: 110/106
    • Valve Lash (Int/Exh): Hyd/Hyd
    • RPM Range: 2200-6400
    It might look like this;
    Static compression ratio of 10.3:1.
    Effective stroke is 2.57 inches.
    Your dynamic compression ratio is 8.21:1 .
    Your dynamic cranking pressure is 165.35 PSI.
    V/P (Volume to Pressure Index) is 135..........................................135VP

    Here's a stock 340
    Static compression ratio of 10.5:1.(I cheated a bit,lol)
    Effective stroke is 2.57 inches.
    Your dynamic compression ratio is 8.37:1 .
    Your dynamic cranking pressure is 169.53 PSI.
    V/P (Volume to Pressure Index) is 134..........................................134VP

    So you haven't lost any bottom end, compared to the stocker.That's a rarity.


    If you want to run both 1/8 and qtr with the same combo; I recommend this;
    An A833 with the 3.09 low,and 3.91s. And with two sets of slicks. This will get you a starter gear of 12.08
    And it might make 93@6065 in third gear, with the 28s.
    And it might make 116@5860 in 4th, with 26s.
    qtr ET might suffer a tad, but Sabest Icando.
    If you move up a cam size, the 4.10s are back on the table, and the so might be the 2.66low box.
    Remember; if you cam your engine to spend a lot of time over 6000, the oiling mods are highly recommended. At 6500 they are mandatory, to keep the rod bearings alive.
    For a track only car I would VooDoo that 350 to the nuts!
     
    Last edited: Oct 8, 2017
  3. 1969GTS340

    1969GTS340 FABO Gold Member FABO Gold Member

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    That is a whole lot of calculations for sure lol. I think I'll stay on the current path with the parts I've collected, get it assembled and ready for opening test and tune night at the track in the spring. I've been calling this project Phase One with the a 7.50 target in the 1/8th. From there I'll inch my way lower depending on cost of each 1/10th lol.
     
  4. MOPAROFFICIAL

    MOPAROFFICIAL FABO Gold Member FABO Gold Member

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    One of you knows that it's about pressure while the other doesn't. Lmao

    Let the ejabucated deside...

    M.s. for satirical purposes.
     
  5. MOPARMAGA

    MOPARMAGA FABO Gold Member FABO Gold Member

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    I have stock rockers on my rt Dakota, works just fine
     
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