Your thoughts on stroker block build

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  1. =Max Wedge=

    =Max Wedge= FABO Gold Member FABO Gold Member

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    Hi All,

    Looking to build a stroker engine. It will be a 4" crank, I beam rods and forged pistons. I know there's a lot of combos out there but, block wise for the rotating assembly described, should I go;

    • 360 magnum because of the roller cam block.
    • 360 LA
    • 340 LA because of bore
    Thanks in advance All.
     
  2. abodyjoe

    abodyjoe Well-Known Member

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    What about the LA roller 360.
     
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    • =Max Wedge=

      =Max Wedge= FABO Gold Member FABO Gold Member

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      Abodyjoe Would that be a set up to go with that rotating assembly? Thanks sir.
       
    • 273

      273 Well-Known Member

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      You gonna use a hydraulic roller cam ?

      If you can find a reasonable priced 340 but I wouldn’t overly worry about it.

      LA 360/ roller LA 360 can use any magnum or LA type head. Magnum can use LA type heads with some work.

      Any really, roller LA 360 gives you most options but you can get roller for normal 340/360.
       
    • Oldmanmopar

      Oldmanmopar Going left turning right FABO Gold Member

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      340 is a bigger bore to start with. The most important choice for me would be the pour number. The lower the number the less porosity . 340-1 being the best and 340-8 and up being the worst. The lower numbers seem to always sonic test thicker and more consistent bores. One thing to remember is once you stroke it there is more side load on the bore.

      I had one let go at 7500. The only thing that remained from the cylinder was the studs hanging out of the head. The piston poked its way through the bore and all I heard was the sound of marbles in a can. Oiling the tires at the end of second on the street is not an experience I'd would want to relive.
       
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      • 12many

        12many Well-Known Member

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        Last edited: Jul 10, 2020
      • Cudafever

        Cudafever Well-Known Member

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        The best thing about a stroker is that you can make power with out revving the shit out of it.
        I when with a 72 .030 360 block

        I when with an all forged lightened (not a light crank or alu rod)4.0" stroker kit had it balance to 7500 rpm, Did the oil mods in the block, Did NOT do any of the valve train trick to turn 7500 rpm, Bolted on a set of RHS heads with my roller rocker arms and a hyd roller cam, that make grate power but falls asleep by 5800 rpm.

        I built a bottom end to will withstand craze rpm(in my mind) but it will take a lot more then a Good Flowing Cylinder Head to make that power safely.

        If i had to do it over again...
        My 12.8: compression would be 10.8: to 11.0:, and run it on pump gas with a little racing gas when i when to lower elevation.
        I would have taken the time to go "Mechanical Roller" instead of Hyd roller.......and i guess, that is the one flaw, in my 7500 rpm short block........You can't turn a Hyd roller much over 6000 rpm. and i wouldn't want to turn a flat tappet that high or with that much spring pressure.
        Ok i have flapped my jaw way to much this morning.
         
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        • MOPAROFFICIAL

          MOPAROFFICIAL FABO Gold Member FABO Gold Member

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          Same sound mine made, '77 360 @.040 no.5 went to pieces. You could see it had some water jacket side pitting/thin spots, even the fracture looked half n half, fresh n old...like it formed early and waited to finish on the track. The very thick milodon tray and oil pan contained it all. Pulled plug on no.6 and coolant shot out over the fender...
           
        • j par

          j par Well-hung Member

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          I have a 360 la that I did Scat cast crank Scat I beam rods and forged pistons...
          .040 over=410..
          put way too much money into Factory heads and if I could have done it again I would have bought the speedmasters on sale and put them on right out of the box with a little cleanup and inspection and re lubrication... In hindsight I would have kept my 273 rockers as the Hughes rockers didn't set the world on fire for what I paid for them... No regrets in a plain solid lifter cam with no rollers....
          Just have to use the correct oil...
          I would have kept my compression down just a little lower so I could just drive up and get pump gas instead of having to add a little race gas...
          That's my hindsight take it for what it's worth....
           
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          • autoxcuda

            autoxcuda Well-Known Member

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            What horsepower was is making roughly?

            What track times was running before this?

            What rear tire type and width?
             
          • Oldmanmopar

            Oldmanmopar Going left turning right FABO Gold Member

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            It was a sprint car going into the turn. Your questions do not pertain. Torque and load take a strong block. That was with a front and mid plate. Pulling on the mount ears make them even weaker. No transmission direct drive. 340-1's are highly sought after for 358's. When you compare them to other blocks you can see the quality difference in the iron
             
          • flyfish

            flyfish C8H18+N2O = :-D

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            Take your pick, I don't think it matters much.

            For what its worth, my 408 uses a 70's 360 LA block with Scat forged crank, Scat I-beams, Forged Icon pistons, 13:1 compression on e85, Ported Edelbrocks and a solid cam....Runs low 10's.
             
          • Demonracer

            Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

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            My bracket Demon is an early 70's block bored .060 with a forged 4" crank, aluminum rods, 12.5 to 1 forged pistons, ported Edelbrock heads, Holley strip master intake, 4779 4 point idle circuit carburetor, solid roller cam, 904 w 4600 stall converter, 4.56 gears & 29.5 x 10.5 slicks. Runs mid to low 9's across the stripe at 6400 RPM's & the cars weighs 2500 +/- with me in it.
             
          • rumblefish360

            rumblefish360 So close, yet so far away FABO Gold Member

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            Would you care to share what block was used and your cam specs?
            (Even though it’s probably listed in the bracket section...)
             
          • Demonracer

            Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

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            71 LA block, cam is Comp special solid roller grind for Hensley Racing. I don't want to give away all of my secrets Rob.
             
          • rumblefish360

            rumblefish360 So close, yet so far away FABO Gold Member

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            :rofl:

            Of course not... but it did t hurt to ask anyway...
             
          • fishmens67

            fishmens67 Well-Known Member

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            If I'm building a small stroker it would only be with a roller block
            Starting from scratch ,why not ?
             
          • =Max Wedge=

            =Max Wedge= FABO Gold Member FABO Gold Member

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            I wasn't sure if there was a trend on a certain block that was superior than the other because of casting or roller or __________ (fill in the blank). Thanks all.
             
          • flyfish

            flyfish C8H18+N2O = :-D

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            Dang...may car is fat, lol! My Barracuda is 3250 with my 175 lbs in it. How did you get your car so light? Tube chassis?
             
          • Demonracer

            Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

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            Glass nose, doors, deck lid, no inner fenders, 60% firewall aluminum, 40% floor aluminum, & poly carbonate windows. And, I got really lucky because after all of this, my weight break is 50/50, 1250 front, 1250 rear.
             
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            • rumblefish360

              rumblefish360 So close, yet so far away FABO Gold Member

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              Nice! This is the route I am going.
              Did you replace all the window glass?
              Also, what material did you use for a roll bar?
               
            • Demonracer

              Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

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              The only glass that isn't poly are the 1\4 glasses, as far as the roll cage goes, it was in it when I bought it. All I've done so far is add a new horizontal bar 6" higher than the original to accommodate the shoulder belt height.
               
              Last edited: Jul 13, 2020
            • j par

              j par Well-hung Member

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              I haven't heard of a bad casting..
              Some like the roller lifters of the magnum and some like the shaft rockers of the LA .. I believe the 89-91 transition block has both. The running consensus is any of them do well but the HP limit for any stock block is around 600... After that most would be looking for a after market block...
               
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              • Idaho

                Idaho Well-Known Member

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                One thought in considering cost. The magnum head adds expense unless you stay with factory rockers. One expert says they are good to .525 lift. I planned to go that way but did not like how much contact angle this produced on the valve stem. Wound up buying Harland Sharp adjustable roller rockers. There is a way to use chevy roller rockers but even they are kinda spendy.
                 
              • Krooser

                Krooser Reform School Graduate

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                I think the 4" cranks are way too heavy. My 3.79" weighs 63lbs! Ok it's a steel billet but still I'd sooner build with a large bore and a short stroke...
                 
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