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Vortec Heads on a 305?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ironmikek5, Jan 8, 2002.

  1. ironmikek5

    ironmikek5 1/2 ton status

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    Now, I know that most people think of a 305 as best used for a boat mooring, but...

    I've got a strong-running 305 that I'm trying to spice up and get more horsepower out of...the engine came from my 83 Jimmy, which has a new Crate 350 in it. The engine is going in my El Camino that I bought on the cheap without a motor.

    I'm planning on dropping the motor in, dressing it up a bit, and selling the vehicle to get more cash to spend on my 83 Blazer. What I'm wondering is, with the Edelbrock Quad and performer intake that were on the 305, would a pair of Vortec heads add any significant horsepower? The engine was pulled from my 83 Jimmy, but it is an 86 305...I'm unsure of compatibility of the heads with a 305 application, combustion chamber size, etc...

    One big question - would the performance increase be worth the cost of the heads, considering my plans for the car?

    Any opinions/suggestions appreciated.

    <font color=red>I will not tolerate intolerance </font color=red>[​IMG]
     
  2. HarryH3

    HarryH3 1 ton status Author

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    You'll have to buy a new intake to go with the heads. The Vortec's have a totally different bolt pattern for the intake. [​IMG] Given that you're going to sell the car anyway, just drop the 305 into it and dump it. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  3. 1bigk10

    1bigk10 1/2 ton status

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    The 305 block is pretty much the same as any other chevy small block with the exception of two bolts on the intake there are two bolts half way down the heads one on each side that are set at a different angle for the 305 heads you may have to elongate those holes to bolt the to your vortec heads Maybe? I hope this helps

    And whenever looking for more power no matter what the engine is better flow as well as more flow are the most important thing, the amount of power you can build is directly effected by how much air you can efficiantly move into and out of an engine.

    1982 K10 Silverado. [​IMG] 327 SHPE powerplant SM465/205,15"custom lift 38.5"TSL/SWAMPERS 12boltrearD44 front,3.73 gears.
     
  4. 1bigk10

    1bigk10 1/2 ton status

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    ThaTts good info i had no idea the vortec heads had diff bolt pattern.

    1982 K10 Silverado. [​IMG] 327 SHPE powerplant SM465/205,15"custom lift 38.5"TSL/SWAMPERS 12boltrearD44 front,3.73 gears.
     
  5. ironmikek5

    ironmikek5 1/2 ton status

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    Thanks for the info, guys. I know they would add more power, I'm just curious about the cost/benefit thing.

    After all, as I told my wife, I'm going to sell the El Camino anyway... [​IMG]

    <font color=red>I will not tolerate intolerance </font color=red>[​IMG]
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Do you think you'll get an extra $700-1,000 for the El Camino if you do the extra work to the engine? If not, then why bother? You're looking at around $700 in parts, plus your labor for the install if you change the heads and intake.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  7. xnoahx

    xnoahx 1/2 ton status

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    Isnt the bore on a 305 different than on a 350? I mean, there is more space between each cylinder than on a 350. so you might loose some compression. I've heard of people putting 305 heads on 350's but never the other way around

    My 73 K5 <a target="_blank" href=http://www.geocities.com/xk5blazerx/73k5.htm>http://www.geocities.com/xk5blazerx/73k5.htm</a> 350/TH350/NP203, Q-jet, Edelbrock intake, Vortec heads, 4" lift, and 36" TSL's
     
  8. ironmikek5

    ironmikek5 1/2 ton status

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    Natural reaction - it is mine now, I want it to have power, go fast, look good... then I'll dump it. Maybe I'll by the Vortec heads and put them on the 350 in my Blazer. That makes more sense.

    <font color=red>I will not tolerate intolerance </font color=red>[​IMG]
     
  9. txbartman

    txbartman 1/2 ton status

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    That makes a LOT more sense. Most of us know we would never get out of our rigs what we are putting into them. But we do it because we have no intentions of selling them. However, for a vehicle you are planning to sell, build it the most cost effective way that you can so that you can sell it, make some money, and have piece of mind that you sold someone something that was worth what they paid (that's why I didn't say cheapest). That's my .02.

    Brian
    Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!
     
  10. 79Jimmy

    79Jimmy 1/2 ton status

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    Vortec heads are available for the 5.0 (305) and the more common 5.7 (350). The 305's are 58cc and the 350's are 64cc combustion chamber size. Casting # for the 305 is 12552520 and 12558059 just off the top of my head[​IMG]

    James

    jimmy79@shaw.ca
     

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