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vortech heads

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by TexasK5er, May 12, 2000.

  1. TexasK5er

    TexasK5er Registered Member

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    I am looking for aset of vortech heads that have been redrilled for pre vortech use. My blazer is an 87, so I think that has the old style intake.

    Nail It!!!!
     
  2. Emmettology 101

    Emmettology 101 3/4 ton status

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    The best way to tell which intake you have(new style or old style) is look at the center two bolts on each side of the intake.
    On the old style the bolts go in on an angle.

    On the new style, the bolts go in straight up and done.

    Or a little easier way. Look at all the other bolts, they all go in on a slant or angle. If your center two bolt (on either side) look like they go in on the same angle as the rest, you have an old style intake. I fthey are on a different angle than the rest(straight up and down) you have a new style intake.

    Another option you have is to drill out an old style intake(if that is the style you have)
    Since the Vortec head WILL have the straight up and down center bolts, you can oblong the center holes on an old style in take so the bolt will line up with the new style heads.
    Hot Rod Magazine did this about a year ago and most machine shops can oblong the holes or you can do it yourself, it shouldn't be too hard.(I will be re-drilling an old intake for new heads in about a month or so.)

    Hope this helps.

    Mike
    82 GMC Jimmy "Emmett"
    IN TOO DEEP Off-Road Club
     
  3. Blazer1970

    Blazer1970 1/2 ton status

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    Mike is a little mixed up on this. There are three types of small block intakes. The original style has six bolts on each side, with all of the bolts perpendicular to the the mating surface between the intake and the heads. If you buy a set of Vortec heads from someplace like Pace, that are modified for the old style intake, this is the pattern that is copied. Your '87 TBI truck has the second style, which is basically the same, except the middle two bolts on each side are straight up and down (vertical). The stock Vortec heads only have four bolts on each side, and they are all straight up and down. The intake bolt holes in the stock Vortec heads are not even close to the same locations that either of the older style intakes use.

    Tim

    1970 Blazer CST 4X4 350 SM465 NP205
    1987 Suburban 4X4 350
    1988 Chevy Pickup 4X4 350
     
  4. Blazer79

    Blazer79 1/2 ton status

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    I think it was 73K5 who told me something that makes sense to me: The performance gains of the Vortec heads is in the design of the combustion chamber and intake paths. If you modify the heads, you probably won't get as much performance as if you don't modify them and use the right intake. You'll be taking away part of that design.

    I'm planning to install Vortecs too, but I will be getting the non-modified ones and a new Edelbrock Intake designed for those heads. That means I'll have to sell my almost new Edelbrock 2101 intake.

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  5. mpikas

    mpikas Registered Member

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    I’ve been wondering about this. After doing a bit of looking around, I’m thinking that the best solution would be to run the vortech heads with one of the vortech intakes and then an adaptor to mount a stock tb to the 4barrel flange on the intake. Right?

    Is there one with a tb flange on it?
     
  6. coopertwpk

    coopertwpk 1/2 ton status

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    Hey you guys dont understand the vortech aluminum heads are designed for TPI which has injectors at the intake right by the heads they flow great for this style but for carb they suck,The cast heads give better venturi efect meaning the fuel and air is mixed better also aluminum heads are not good for slow high torque motors ,If you do go with them change you antifreeze often otherwise youll have them crack(cast iron and aliminum does not go well together).
     
  7. Jamie

    Jamie Registered Member

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    The vortec heads I have on my 79 (400) are great except for the lack of a heat crossover. If you live where the temp's always above 50 degrees then you shouldn't have any problems. But If you live in a colder part of the country like I do (PA) then you may experiance cold running problems untill It warms up (about 10 minutes in fast Idle). Otherwise there great.
     
  8. '73 K5

    '73 K5 1/2 ton status

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    Yep. The guys I talked to at Burt Greenwald Chevy in Akron Ohio said that if you get the heads drilled out, you'll lose some of the performance gains that Vortec heads were designed for.
    I don't think anyone is thinking about the aluminum ones right? The L31 cast iron ones are the heads that I went with. Got the Edelbrock intake, new valve covers, had to replace my roller rockers with stamped ones, new throttle linkage holder, spark plugs, etc. It was a lot of stuff to change, but I'd do it over again. I could tell a difference right away. They really complement my cam...and ever since I put 4.10 gears in, my Blazer actually hauls ass a little bit.

    '73 K5
    Chevy good...Ford bad
     

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