Maximum Valve Lift?????

Discussion in 'Engine Topic' started by 79_Bird, Jun 27, 2015.

  1. 79_Bird

    79_Bird New Member

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    So I've been building this 1974 Chevy 350 and I recently picked up a new cam from the Hot Rod Barn, and its a little too big for the stock valve springs. This Cam is rated at .510 Lift, I heard the stock springs for the 350 can take like .470-.495 lift without overloading (Mine are 882 Heads). So my question is who makes a good set of springs I can put on these heads, Id like to be around .600 for max lift cause someday I plan to go to a 1.6 rocker arm ratio.
     
  2. Damon

    Damon Veteran Member

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    It's not just the springs. The bottoms of the retainers can hit the tops of the valve guides beyond a certain point. .510" is typically past that point.

    .600 lift is way past the point that the 882 head is going to keep up, even if no parts start colliding with eachother.
     
  3. kimosabi

    kimosabi Veteran Member

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    Is there anything to gain going above .500 lift on the 882 heads? I thought they had a ceiling around .450 lift.
     
  4. 79_Bird

    79_Bird New Member

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    So what would you reccomend on an aftermarket set of heads?
     
  5. Damon

    Damon Veteran Member

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    Hydraulic flat tappet? Solid? Hydro-roller?
     
  6. 79_Bird

    79_Bird New Member

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  7. sschevellefan

    sschevellefan Veteran Member

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    That cam with 1.6 rockets wont be near .600 lift so I wouldnt worry about it. It is way too big for the 882 heads for sure. Its not just the retainer to guide clearance but also spring pressure and the stock springs will flow if you try to spin it high enough for that camshaft to start working. I know several guys who ran similar cams with the Z28 springs but until you change your heads I would not install that cam.

    How is the rest of the engine built? Are you running cast pistons and pretty much stock parts? They dont hold up to the RPM`s that camshaft needs. Without knowing how its built I wont suggest a set of heads or a different camshaft yet.
     
  8. 79_Bird

    79_Bird New Member

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    Scat Cast 383 Stroker Crankshaft
    Scat prostock I-beam 5.7 connecting rods
    SpeedPro Flat top, Hypereutectic Pistons 4.030 bore
    Cloyes Double Roller timing chain
    Weiand Team G intake Manifold
    Holley 750cfm dual inlet
    Proform race Hei distributor.
     
  9. sschevellefan

    sschevellefan Veteran Member

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    First thing is make sure the camshaft clears the rods. The 5.7 rod strokers are notorious for having cam clearance issues.

    I`m not sure why you are even considering using the 882 heads with a build like this. Decent sized hydraulic cam, single plane intake and 750 holley, all of this stuff out performs those heads. with the flat tops you have to watch the chamber size because a 64cc chamber will get you 11:1 depending on your quench and that might not work out too good on pump gas with the hyperutectics. You need to measure your deck height and then pick a head gasket that will get you around a .040 quench. Then look for a head with a 72-75cc chamber. Do you want aluminum or iron? The old school 200cc Dart sportman heads would work great but they are now sold under the world Products name. THey are available in a 72cc chamber. Trick flow has a 72cc 195cc runner head available, Brodix has a IK 200cc head available in a 70cc, AFR has a good head in a 74cc. Just depends on what you want to spend.
     
  10. 79_Bird

    79_Bird New Member

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    Ive been told multiple times about the stroker clearance for the cam. Its a small base circle cam so I may be alright on that. I was just curious about those heads, they are kinda junk anyways and I wanted to see If they were any good I would maybe get them freshed up. Aluminum Heads is what I was thinking, ive been told to stay away from Edelbrock. The Dart SHP series look to be pretty good bang for their buck. http://www.summitracing.com/parts/drt-127422/overview/make/chevrolet at .620 max lift. A 1.6 With that cam would be about .543 valve lift. Plus these heads are towards my budget more.
     

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