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  1. #31
    Vette66AirCoupe
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    Quote Originally Posted by JohnZ
    No such thing as an "098 cam"; the "097" Duntov cam was part number 3736097, and they were ground on core casting number 3736098 (which was also the part number for the raw core).
    Thanks John, that explains the confusion but not the fact that I couldn't get the valves adjusted properly. I'm guessing I got taken advantage as this was a resale camshaft (allegedly only used for one 1/4 mile run at Cecil County Dragway) and I was 17 at the time and didn't know squat from Shinola. Who knows what that camshaft might have been!

  2. #32
    speedmaster4
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    back in the early 60's when you went to the parts counter at the chevy dealer and ordered a service repacement cam for an 097, the part number in the book and on the cardboard tube that it came in....098....i bought a bunch of em.

  3. #33
    Member saopm's Avatar
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    Is there a general rule on compression? What is the highest I can go on 93 Octane? There must be some point of diminishing returns.

  4. #34
    speedmaster4
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    general rule for streetable comp ratio---octane of gas divided by 10 for iron heads,add 1/2 point for soft heads...so 93 octane = 9.3 comp ratio with iron heads, 9.8 with alum heads....many, many other factors can push up or down somewhat, but this simple, stupid method works

  5. #35
    Member saopm's Avatar
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    According to the 1963 Corvette Shop Manual the compression specification for the ’63 340HP motor is 11.25:1. What kind of octane fuel was readily available back then? 110 octane? Or did most people just retard the timing?

  6. #36
    Vette66AirCoupe
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    Quote Originally Posted by speedmaster4
    back in the early 60's when you went to the parts counter at the chevy dealer and ordered a service repacement cam for an 097, the part number in the book and on the cardboard tube that it came in....098....i bought a bunch of em.
    Interesting. So either way the valve lash was the same I would presume. Does .012 and .018 sound familiar (intake/exhaust)?

  7. #37
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    I run 10.0:1 (actually measured and calculated) and it runs fine on 93 with 10 degrees initial timing. I think I could run 91 if I had to.

    11.25:1 was an inflated figure although the 340HP engines came with two steel shim head gaskets to stop some detonation problems. Most people find that they can run up to 10.5:1 on 93 octane with an SHP cam and stock heads. If you're right at 10.5:1, you might have to back off the timing a few degrees.

    I recommend shooting for 10.25:1 with the 097, 30-30, or LT1 camshaft. You shouldn't have any problems.



    Regards,
    Brian

  8. #38
    speedmaster4
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    saopm:

    sunoco 260 was what "everybody" who owned a 'performance' car used... reputed to be 104 octane minimum...after getting a new car,standard procedure was to get a "curve kit" for the distributor--throw away the 'slower' advance springs and just stick on the 'teenie' ones...without headers,gears(rear end), carb rejet, and 'curved' ign--you'd get eaten up on the way to work, not to mention at the strip...pinging or bucking (whole car shakes) meant shift down dummy--retard the timing and loose hp-no way

    vette66aircoupe:
    actually .014/.018 as i recall...but everybody had their 'speed secrets'

  9. #39
    Subfixer's Avatar
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    I'm running a .060 over 327 with 10.5:1 compression and an LT-1 solid lifter cam @ 12*BTDC initial timing with no detonation problems on 93 octane.

    While not an original L76 car, the trans is a WR M20 pushing a 3.36 rear. The lower 1st gear of the WR trans works well in this combo. The torque is "almost" as good at low RPMs as the original 300hp engine was. Big difference in the upper RPM's.

  10. #40
    Administrator Tom Bryant's Avatar
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    Factory recommended clearance for the 097 was .012 and .018. Most of us set the intake to .008 to get a little more intake duration. You will hear a lot of old timers say 8 and 18. Of course the 30-30 cam was .030 and .030. Hence it's name.

    In this area of the midwest regular leaded gas back then was 90 or 91 octane at most stations. Low octane (89 and 88) started showing up in the 60s. Sunoco was one of the first with their custom blending pump which started with 190 (89 octane advertised as an economy fuel that we called p*** water) and originally had every graduation by 10s up to 260 (104). The idea was you could blend your gas at the pump to get just what your car needed.

    Other stations just had regular and premium. Middle grade is a product of the unleaded period. Leaded premium usually was 97 or 98 except for Union76 which was 104. On the Sunoco pump scale 240 (98) was premium and was priced with other brands premium. 250 (100) and 260 (104) were high performance fuels.

    If you had a Union 76 station close by it was the real bargain. Since their 104 premium was their only premium it was priced the same as competitor's premium so you saved a couple cents over Sunoco. The bottom line is that in the '60s you had no problem buying the right fuel at local stations for your 11:1 muscle car with all the timing cranked in it could take.

  11. #41
    Member motorman's Avatar
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    Quote Originally Posted by Tom Bryant
    Factory recommended clearance for the 097 was .012 and .018. Most of us set the intake to .008 to get a little more intake duration. You will hear a lot of old timers say 8 and 18. Of course the 30-30 cam was .030 and .030. Hence it's name.

    In this area of the midwest regular leaded gas back then was 90 or 91 octane at most stations. Low octane (89 and 88) started showing up in the 60s. Sunoco was one of the first with their custom blending pump which started with 190 (89 octane advertised as an economy fuel that we called p*** water) and originally had every graduation by 10s up to 260 (104). The idea was you could blend your gas at the pump to get just what your car needed.

    Other stations just had regular and premium. Middle grade is a product of the unleaded period. Leaded premium usually was 97 or 98 except for Union76 which was 104. On the Sunoco pump scale 240 (98) was premium and was priced with other brands premium. 250 (100) and 260 (104) were high performance fuels.

    If you had a Union 76 station close by it was the real bargain. Since their 104 premium was their only premium it was priced the same as competitor's premium so you saved a couple cents over Sunoco. The bottom line is that in the '60s you had no problem buying the right fuel at local stations for your 11:1 muscle car with all the timing cranked in it could take.
    the 30-30 cam was speced at .025 when it came out but there was not enought vacuum for the FI to run correctly so they changed it to .030
    retired race engine builder,former NASCAR tech inspector,corvette owner since 1959, new corvettes owned,59,62,63,64,65,66,97,99,02,05, 2008 is in my garage, 2008 sold and waiting for my C-7

  12. #42
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    Is the LT-1 cam referred to in this thread the same cam that was in the 370 hp solid lifter Lt-1 350 crate motors around 1970?

    ~Stan...

  13. #43
    Administrator Tom Bryant's Avatar
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    Yes. Also in the Z28 and '70-'72 Corvette LT1

  14. #44
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    Quote Originally Posted by Subfixer
    I'm running a .060 over 327 with 10.5:1 compression and an LT-1 solid lifter cam @ 12*BTDC initial timing with no detonation problems on 93 octane.
    Subfixer, may I ask what pistons and heads you are running to get the 10.5:1 ?

    Thanks, SS63

  15. #45
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    Thanks Mac...I have a few other questions too.. I'll start another thread rather than hijack this one...

    ~Stan..

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