Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Vortec spring lift? and what is the compression of a Vortec 350?

Discussion in 'The Garage' started by sled_dog, Apr 23, 2004.

  1. sled_dog

    sled_dog 1 ton status

    Joined:
    Sep 3, 2002
    Posts:
    16,870
    Likes Received:
    0
    Location:
    Austin, TX
    I seem to remember vortec springs can only take .450 lift am I correct? I am going to change the intake and head gaskets on my 97 soon and I was thinking while I am that far why not put in a nice torquey cam and do some head work to it. The 2 cams I'm looking at are the comp cams XR252HR and the XR258HR. see specs here
    Both have like .470+ lift. Also anyone know what compression my 97 350 has?
     
  2. u2slow

    u2slow 1/2 ton status

    Joined:
    May 9, 2001
    Posts:
    2,217
    Likes Received:
    0
    Location:
    BC Canada
    Stock Vortec spring are considered weak to begin with. Any performance cam should have better springs installed with it.

    I thought it was the slot in the slot rocker that limited the lift, rather than the springs themselves /forums/images/graemlins/thinking.gif
     
  3. K5Chris

    K5Chris 1/2 ton status

    Joined:
    Mar 11, 2002
    Posts:
    805
    Likes Received:
    0
    Location:
    New Orleans, LA
    i didnt look at the specific model cams your looking at, but you are looking at roller cams right? the stock vortec cam is hydraulic roller. rplacing it with a flat tappet is a downgrade.

    get Z28 springs and LT4 retainers, and you'll be good to go. /forums/images/graemlins/waytogo.gif

    i think the compression is high 9's, maybe 10.0ish? i dunno.
     
  4. sled_dog

    sled_dog 1 ton status

    Joined:
    Sep 3, 2002
    Posts:
    16,870
    Likes Received:
    0
    Location:
    Austin, TX
    yeah cam is roller, I think I'm not gonna bother with the came now, cams run like $350(I knew Hydraulic roller wouldn't be cheap) so just some head work, maybe do the springs and retainers to save that work in the future.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,977
    Likes Received:
    189
    Location:
    Roy WA
    .450" lift on my vortec heads, is about max. I ran out of valve spring retainer to valve guide clearance.

    Putting a .452" lift roller cam in my older block, I had to cut quite a bit of material off of the Vortec's around the pushrods. The holes are pretty small, and the pushrods contacted the head at almost every cylinder.

    Vortec cam lift is something like .420", so an aftermarket cam is almost certainly going to require more seat pressure, and with Vortecs, you start getting into special springs at that point, with very little variety, OR have your heads machined.
     

Share This Page