Looking for some advice for a change

Discussion in 'High Performance Modifications' started by jvle95, Feb 1, 2018.

  1. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    Mar 25, 1999
    San Jose, CA, USA
    You can get away with a little bit more duration; compression is on the low side to go crazy.
    I'm liking the Crower 00484 for this one. Duration @ 050 jumps up to 230/236 but it also spreads out the lobe separation to 114 which will keep the idle from getting out of control and widen the powerband. The 545 / .555 lift is going to open up those AFR heads nicely.

    Keep in mind, you are going to need lifters, springs pushrods etc to support this. You'll probably have ~ $1400 into the upgrade all said and done.
     
  2. jvle95

    jvle95 Veteran Member

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    May 14, 2007
    SF Bay Area, CA
    I was anticipating around $1200 for a roller cam set up and depending on which cam I went with I may have to look into a convertor change as well. Its been a while but from what I remember when I ran the Comp 280/480 cam I have idle issues because my convertor was too tight. I did eventually switch it to a 10" 3000 rpm stall (forgot the brand) and that made the idle issue workable. With the tight convertor (2200 to 2400 stall) the car would idle great until you put it in gear. The looser convertor kept it from surging and bogging the idle down.

    Lowend, the Crower you mentioned above is interesting and I will look more into that as well. Never run anything with a 114 lobe seperation. I will do some reading to get myself schooled up.
     
  3. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    Mar 25, 1999
    San Jose, CA, USA
    Wider lobe separations came back into vogue in the aftermarket about 15 years ago. Initially, they were being used to keep manifold vacuum up for use with EFI; than people realized the cars were going faster regardless.

    Basically, the wider lobe separation is allowing you to run more duration on the cam, without as much valve overlap. So higher RPM range, without destroying the idle (note: this is way oversimplified).

    The OEM's have known about wide lobe separations for a long time; The 1970 LT-1 Cam used a 116 Lobe Separation as did the 1993-1996 LT1 both engines could be considered "peak" small block for their time
     
  4. 2ndGenCrazy

    2ndGenCrazy Veteran Member

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  5. jvle95

    jvle95 Veteran Member

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    May 14, 2007
    SF Bay Area, CA
    Submitted, just waiting on reply.

    Thanks
     
  6. 77 cruiser

    77 cruiser Veteran Member

    486
    14
    Nov 17, 2006
    Frostbite Falls MN
    Let us know, you'll probably think it's too small.
     
  7. 77 cruiser

    77 cruiser Veteran Member

    486
    14
    Nov 17, 2006
    Frostbite Falls MN
    Did he get back to you?
     
  8. jvle95

    jvle95 Veteran Member

    157
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    May 14, 2007
    SF Bay Area, CA
    Funny you should ask, just received reply today.

    HR70340-110
    224/228 @ .050"
    .340"/.340" lobe lift
    .544"/.544". valve lift, w/ 1.6 rockers
    110 LSA

    I would probably need to do a valve spring replacement as well but looks like it might wake up the little mouse a little.
     
  9. 77 cruiser

    77 cruiser Veteran Member

    486
    14
    Nov 17, 2006
    Frostbite Falls MN
    I just got one back from him today too. Quite a bit diff. than my current cam.
    Straub cam 227/239 .359/.341 107lsa
    Jones cam 232/240 .360/.365 112lsa
     
  10. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    Mar 25, 1999
    San Jose, CA, USA
    To display all three cams apples to apples
    Crower 230/236 .363/.370 114 lsa
    Straub 227/239 .359/.341 107 lsa
    Jones 232/240 .360/.365 112 lsa



    The Straub cam, I'm not liking. He's giving you a lot of extra duration on the exhaust, but with lower lift on the exhaust side. The whole reason for extra duration on the exhaust side is compensating for Chevy's crappy exhaust port; Using a lower lift seems a little self-defeating. With that tight of a lobe separation, think the powerband is going to be somwhat narrow. This cam reminds me of an Isky I used to sell people who wanted a choppy idle but didn't have the gears or compression to support a lot of duration. Sacrificed some power to get the lopey idle.

    The Jones cam is very similar thinking to my Crower, but the Crower has a lot more aggressive ramps (less duration, more lift).
     

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