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vortec heads

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by timebomb1602, May 8, 2001.

  1. timebomb1602

    timebomb1602 1/2 ton status

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    Hey anyone using vortec heads? I have a 91 with tbi, will the edelbrock tbi manifold bolt up to them? Also do they have room to be ported much?

    <font color=red>1991 GMC Jimmy 350tbi 3.42</font color=red>[​IMG]
     
  2. BlazinRojo

    BlazinRojo 1/2 ton status

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    One problem is that the vortec heads go to a different bolt pattern (i believe it is 4-bolt instead of six) so your old manifold won't fit (i think; somone else confirm this).
     
  3. Pure Insanity

    Pure Insanity 1/2 ton status

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    i run them.the heads have a strange bolt pattern on them ive heard you can get them drilled to accept early manifolds(pre 86)ive never talked to anyone thats had them drilled,i bought a performer rpm for vortec.then again im the only person i know personally that runs em.they say 20-40 horse gain outta the box.i think scoggin dickey is where i seen them drilled to accept early manifolds.i know several people that have modified early intakes to go to 86 up heads. i dont see why it cant be done the other way.i dont know about porting them i didnt bother.ive been told by a circle track guy that they flow better than the famous 202 double hump heads.i dont know for fact but thats what i was told.

    PURE INSANITY
    86 blazer see it at:<A target="_blank" HREF=http://www.zing.com/album/pictures.html?id=4292792569>http://www.zing.com/album/pictures.html?id=4292792569</A>
     
  4. Sparky87k5

    Sparky87k5 1/2 ton status

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    I'm running a set of Vortec heads on a 383 roller cammed stroker and use the Edelbrock RPM with a 650 Holley. Vortec's definitly take a different intake then the earlier heads. Vortec's are excellent choice for low end torque and fuel economy.

    Gone fishing
     
  5. ftn96

    ftn96 1/2 ton status

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    NO, the intake your are refering to will not bolt up. There is a vortec conversion kit you can buy, it comes with the heads, the intake, and all the gaskets and everything you need for the install. You can order it from paceparts.com
    The kit costs 1059.95. It even comes with the exhuast manifold to fit the new heads. I saw the article in this months Carcraft mag.

    Will work for beer, parts and tools.
    90-350TBI-TCI700-241-33"-10/12 bolt w/4.10's,
    <A target="_blank" HREF=http://www.nashvillek5.freeservers.com>http://www.nashvillek5.freeservers.com</A>
     
  6. '73 K5

    '73 K5 1/2 ton status

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    Yea, the Vortec heads made a huge difference in my Blazer's performance. Do a search for "Vortec" and you should find quite a bit of info. This has been discussed alot in the last several months.

    '73 K5
    Chevy good...Ford bad
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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  8. Pure Insanity

    Pure Insanity 1/2 ton status

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    i think scoggin dickey has em already drilled

    PURE INSANITY
    86 blazer see it at:<A target="_blank" HREF=http://www.zing.com/album/pictures.html?id=4292792569>http://www.zing.com/album/pictures.html?id=4292792569</A>
     
  9. CaptCrunch

    CaptCrunch 1/2 ton status

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    The vortech heads that are drilled for the old style manifold are designed for short duration use only. They were invented by circle track racers. Used on an everyday time application or even an occasional driver they will leak.

    For the guys w/ the vortechs on now I'm interested on whether you upgrade to screw in studs... and what kind of valvetrain componets you have gone with. Specifically I have the orignal press in studs and am trying to figure out what rockers to use on it w/ a hydralic lifter valvetrain. I know have read about some complictions w/ rocker arm selection.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  10. CaptCrunch

    CaptCrunch 1/2 ton status

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    oh yeah... porting can be done on them, but stay out of the combustion chambers. They are specifically shapped and this shape gives a lot of the benifits of the heads...

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    I know that I am far from authoritative "it works" territory, but I have mocked up my vortecs with crane cams pro magnum(?) solid steel full roller (fulcrum and tip) and stock center bolt valve covers.

    I am keeping the press in studs. GM used press in studs since at LEAST the late 60's, and some of those motors are still running. Yes, they loosen up. My dad just had a pair of original '68 327 heads redone, and the studs were just getting loose. 33 years of use will do me fine. I would have done screw in, but the cost, especially since the heads are brand new, wasn't worth it to me. It's not like you need guide plates if you use the correct rockers anyways, so besides high lift/high rpm applications, the stock studs are fine. Like I said in an earlier post, I know a guy that is still running them (hard) with the stock studs and springs (supposed .450 max) with a .485 lift cam. I wouldn't press my luck since mines a daily driver, so I decided on a roller cam that has max. lift of .452.

    Anyway, on mockup, with the wider(wider than AL ones anyway) steel roller rockers, I MAY have to do a tad bit of clearancing on the center bolt support brackets inside the valve cover. But other than that, full roller rockers appear to fit fine, as long as lift is kept relatively low.

    The term "rail" rocker threw me for the longest time. that is actually what the vortec rockers are...there are two "rails", one on each side of the rocker tip, to keep it from slipping off the valve stem. I guess Ford has been doing this for awhile, because even before the Vortecs I saw teh term "rail" used in conjunction with "ford"

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  12. CaptCrunch

    CaptCrunch 1/2 ton status

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    I am doing about the same DY. Figure I'll be ok w/ the stocks stuff on there cause it is obviouly a low rpm truck. Roller, roller, roller... everyone going roller. I really don't see the benifits in a daily driver, low rpm application to justify the cost. All the roller stuff is going to add up to 600+ dollars or more if i use the good stuff. Really blows me away when I can use some brand new in the box Comp Cam lifters I have in the garage and spend about 300 on the rest. I dunno...

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    I have a hard time justifying the roller stuff as well. I tried with the math, I tried with the performance, it IS hard to justify the added expense.

    One way to look at it is this...it takes just over 40HP to keep our truck moving (aerodynamics) at around 60mph. With roller stuff (using same specs as flat tappet, standard rockers) your vehicle is now being moved at 60MPH without "losing" that 40 or so HP, since the roller cam and rockers will "add" that much HP.

    This would apply at all RPM's though, so to get you moving, and keep you moving, the throttle necessary would be less..now you are getting into the "well, it may take less throttle, but if I use the same amount of throttle as before, now its faster!" lol

    But, now that I've got enough money to do it the way I'd like to (and the way GM does it now) I figure why not? The motor is a spare, I've started collecting the pieces, so I don't have to worry about the out of pocket expense all at one time.

    If you ask me, my biggest mistake thus far is not going TPI. I think if I found a TPI unit to bolt on for cheap enough, I'd do it...seems ridiculous to me, except in a racing environment wher eyou might be restriceted to carb use, to have all this roller stuff, and not go TPI. I like my carb, but I'm not going to try and say that a carb is just as good, because its not. TPI alone would probably give me the 2MPG that all of these other mods combined will.

    If I were to figure it out economically, adding the roller stuff, AND the Vortec heads I've got to go with it, giving myself a conservative estimate of 17mpg (hoping for higher, since I average 15 now) I figured, with my bad math, that with 2MPG better, and a 30 gallon tank, I would "save" (actually just drive further on the same amount) 4 gallons per tank, which works out, with my driving habits thus far, to $312 per year @$1.50 a gallon.

    I can always use the argument that you can reuse the cam and lifters as well, but lets not kid myself, its gonna take awhile to get to 100k+ miles...but I shouldn't have to worry about bad lifters or cam in that entire time.

    Granted, shelling out the $850 or so I have for the roller cam, lifters, rockers, Vortec heads and intake isn't for everyone, but I think the added performance, maybe increased reliability, and savings in gas are worth it.




    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  14. MudFrog

    MudFrog 1/2 ton status

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    So take my engine for instance.. It's an 89 stock TBI. I would not have to adjust manifold to accept Vortec Heads? What would I have to adjust?

    89 K5 Silverado
    <A target="_blank" HREF=http://mudfrog.coloradok5.com>http://mudfrog.coloradok5.com</A>
     
  15. MudFrog

    MudFrog 1/2 ton status

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    So take my engine for instance.. It's an 89 stock TBI. I would not have to adjust manifold to accept Vortec Heads? What would I have to adjust?

    89 K5 Silverado
    <A target="_blank" HREF=http://mudfrog.coloradok5.com>http://mudfrog.coloradok5.com</A>
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    You would have to get a new manifold to use the Vortec heads. The only TBI intakes I have seen are like $300 right now. Hopefully they will come down in price, or someone else will start making them. I think they are GM only items right now.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     

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