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.

Higher ratio rockers

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Hardcore, Sep 9, 2003.

  1. Hardcore

    Hardcore 1/2 ton status

    Joined:
    Apr 25, 2003
    Posts:
    458
    Likes Received:
    0
    Location:
    New Orleans, LA
    Anybody running higher ratio (1.6) rockers for a little more power. I've always thought the higher ratio rocker gave a little more torque. I'm considering running some with a mild cam in my TBI motor /forums/images/graemlins/thinking.gif
     
  2. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,095
    Likes Received:
    144
    Location:
    california
    I'm thinking the same. I allready have a pumped up 406 with a comp 268H and am looking for a little bit more lift for a lobeyer idle and more power.

    -------------------
    85K5 3/4ton,14boltFF,10bolt,9"lift,35"boggers,16.5x14welds, big horse 406SBC/700R-4 /forums/images/graemlins/k5.gif /forums/images/graemlins/angryfire.gif
     
  3. Beast388

    Beast388 1/2 ton status

    Joined:
    Nov 6, 2001
    Posts:
    3,039
    Likes Received:
    0
    Location:
    Clinton, IA USA
    I am running full roller 1.6 ratio rockers in my 388. With the higher ratio, I have 0.477/0.493 valve lift instead of the 0.447/0.462. The higher ratio does affect duration somewhat but only a small amount. I did feel a small increase in power, but nothing earthshaking. /forums/images/graemlins/thumb.gif
     
  4. bigblock44k5

    bigblock44k5 1/2 ton status

    Joined:
    Jun 8, 2003
    Posts:
    396
    Likes Received:
    0
    Location:
    Hurlburt Field, FL
    They will give you slightly more power, but remember your power band will go slightly higheras well. If this is ok with you and you have the clearance go for it. If not a safe bet on a stock or near stock motor is to get split ratio rockers and put the 1.6 on the exhaust side to help clear the cylinders better due to the small exhaust vavle. Hope this helps good luck.
    Ken /forums/images/graemlins/thumb.gif
     
  5. Hardcore

    Hardcore 1/2 ton status

    Joined:
    Apr 25, 2003
    Posts:
    458
    Likes Received:
    0
    Location:
    New Orleans, LA
    [ QUOTE ]
    If not a safe bet on a stock or near stock motor is to get split ratio rockers and put the 1.6 on the exhaust side to help clear the cylinders better due to the small exhaust vavle.

    [/ QUOTE ]

    /forums/images/graemlins/thinking.gif I read that in a Chevy performance book too, may have to investigate that some more. /forums/images/graemlins/thinking.gif /forums/images/graemlins/thinking.gif /forums/images/graemlins/thinking.gif
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,977
    Likes Received:
    189
    Location:
    Roy WA
    I could be wrong, but I thought the gains from this were really not that large. Gotta be SOME article online that has a before/after dyno test shown.

    Obviously a lot of the difference is based on how much power the engine made before the rocker swap.
     
  7. R72K5

    R72K5 Banned

    Joined:
    Mar 5, 2001
    Posts:
    8,905
    Likes Received:
    0
    Location:
    central IL
    some pontiac and oldsmobile engines and some straigt six engines got higher than 1.5 ratio rockers, id have to look again to see what years and applications got them.

    buick 250 got 1.75 rockers
    buick 350 1.55
    buick 455 1.55 to 1.6 depending on year
    chevy 400 402 454 1.70 to 1.50 dependingon engine and year
    chevy 153 1.75
    chevy 230 1.75
    chevy 250 1.75
    caddy 500 1.72
    caddy 472 1.72
    pontiac 250 certain years 1.75
    pontiac 151 1.75

    theresmore but thats alot of them through 70-77 years
    i just threw away a frozen chevy 250 i could hav taken the 1.75 rockers from, and i didnt realize, it too late now, hehe
     

Share This Page