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383 and heads

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by ftn96, Oct 31, 2001.

  1. ftn96

    ftn96 1/2 ton status

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    Whats are the best all around heads for a 383 or is there a post that already has this info?
    I talked to speedomotive. They normally use sportsman II 72cc heads if I recall with 200cc runners.
    I was looking at getting the vortec's but they only come in 64 cc and 170 cc runners. I was wondering if It would start crapping out on me after 3500?

    Also if I go with the 64 cc heads Im gonna have to use dished pistons to keep me down below 9.5-1.
    So whats the best deal here? should I get the 64 CC vortecs with dished pistons and pray, or dig aorund and find some 76 heads somewhere and run flat tops? I like the idea of the flat tops, so I can get the most out of the cylinder but..... I need some good info from you guys.
    Come on now its Hell-oween!!!

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  2. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    Scoggin-Dickey sells a lot of that stuff you might check them out, they just joined today as an advertiser, their banner is in the rotation.

    Steve

    Bandwidth FREE ZONE

    Mall-Running poseur 4x4 with curb-feelers
     
  3. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    I like the idea of dished pistons and 64cc heads with around 9.25:1 compression ratio. I think this would produce very good flame travel, and the Vortec's are already known for their good burn characteristics. If you aren't looking to turn the motor to 6000 rpm then you dont need the 200cc runner volume anyway, it would just hurt low end torque. Decisions, decisions!

    Just my $.02

    '85 K5 : Run it til it breaks, then fix it and go again!
     
  4. ftn96

    ftn96 1/2 ton status

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    Ok, now thats good news. I was really leaning toward the Vortec's and the dished P's....but wasn't sure of the possible side effects.
    If I get a mild cam will I need to replace the springs on the vortec? Say like the 12242-2 Comp cam?

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  5. HarryH3

    HarryH3 1 ton status Author

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    Sweet! Any special deals from Scoggins-Dickey for ColoradoK5.com'ers? [​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...
     
  6. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    The factory springs can handle up to .465 lift.

    '85 K5 : Run it til it breaks, then fix it and go again!
     
  7. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    I will bug him some more. [​IMG]

    Steve

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  8. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    I almost forgot, SD is a Chevy dealer too.

    Steve

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  9. fad2blk99

    fad2blk99 1/2 ton status

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    I've used Scoggin-Dickey for tech info before. They know their stuff, and will know doubt have just the thing you need at the best price. -- I swear this is not a paid endorsement!!! :) I'm just a satisfied customer. One down side though is they are all the way out in Lubbock, Texas.
    Check out their web site at www.sdpc2000.com, Its pretty cool!

    <font color=black> -Tommy
    <font color=red>"To secure peace is to prepare for war..."
     
  10. ftn96

    ftn96 1/2 ton status

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    I've been to their site and got some info from them. But since have changed my mind.
    Im getting the speedomotive budget 383 strocker kit and installing it into a mid 70's 2 piece rear main seal block.
    I figured out that the set of heads I have laying in the garage are 1.94 1.50 heads. The casting number is 3998898, which is not listed on mortec.com. But the number 3998897 is and its a 76 cc head. So Im hoping that someone here can help me verify that these heads are 76 cc. If they are, they are going to the head shop for a re-work and they will be the heads I use. This will keep me at 9.4-1 with flat tops.
    Any info guys? Please help me. Im ready to start ordering parts.

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  11. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Go with Vortecs or aftermarket....you'll be much happier when you've got that much motor to feed. If you go Vortecs, some minor porting never hurt either.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  12. tkettwig

    tkettwig Registered Member

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    I'm running a 383 in my Blazer and i just used a stock set of heads,76cc. flat top pistons and had a real problem running anything but Hi octane gas, Gas isn't cheap here so I would think hard about the dish pistons.
     
  13. ftn96

    ftn96 1/2 ton status

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    From what I understand a 76 cc head and a 383 with flat tops would give a 9.4-1 which would call for at least 91 octane.

    Ok, so If I go with the vortecs and the dished P's and maybe a thicker gasket, what else will I need to do to the heads to get them ready to rock, other than new springs for the cam Im using?

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  14. MUDNUTT

    MUDNUTT 1/2 ton status

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    go with the vortecs. for a couple dollars more than rebuilding your 76cc head you have a brand new fully assembled head(i got mine from my local chevy dealer and they were cheaper than scoggins and i didnt have to pay shipping) and a bonus is that the vortecs are the best flowing iron head chevy ever produced. you would have to pocket port the 76cc heads to get them to flow anywhere near the vortecs out of the box. i run the vortecs on a rebuilt 350 w/ flat top 4 valve relief pistons and an erson tq-20 cam and have had no proplems w/ the combo yet. you have to run a dedicated manifold w/ the vortecs as the mounting is different but that is just a reason to step up to a performer rpm manifold.

    <font color=blue>DRIVE IT LIKE YOU STOLE IT[​IMG]
    <font color=red>PROUD TO BE AMERICAN[​IMG]
     
  15. ftn96

    ftn96 1/2 ton status

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    Yeah, but I gotta get the TBI/Vortec manifold as Im dedicated to keeping my TBI unit, less someone can convince me that a carb is better. [​IMG]

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  16. '73 K5

    '73 K5 1/2 ton status

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    I love my Vortecs man...you should go with those. And if you do get them, DON'T port them. I've read several articles and talked to a few people about how testing has shown that 99.9% of the time that porting will lessen performance on those heads. Just take them out of the box and bolt them on.
    Also, you can run higher compression with the Vortecs than you can on old stock heads and run the same gas. Its called "fast quench" or "high quench" or something, but basically its describing the combustion chamber and it aids in preventing detonation from higher compression.
    I've got stock pistons, Vortecs and I can run 89 octane on all but the hottest days...then 91 octane does fine.

    '73 K5
    Chevy good...Ford bad
     
  17. ftn96

    ftn96 1/2 ton status

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    Well, I called the local dealer and they wanted 319 each for them. So as far as I can tell its gonna be cheaper to get them from Dicky's.

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  18. You only need big runners when you get into the higher rpm's.The smaller port design helps low end torque because of port velocty at the lower rpm's. The vortec heads are good for a little of both because of the combustion chamber and port designe.I agree with the dish pistons and vortec heads!!
    If you don't mind messing with your timing you can turn your initial timing up a little in the winter and down a little in the summer to compensate for the air density.Say maybe 8-10 deg. in winter and 5-6 deg in the summer. Just play around with it and see what works best on your rig.

    The best thing is to get an msd box (or equivalent) with an adustable timing control that you can dash mount,or ad later.
    This also helps keep the cunbustion burn more efficiant.
     
  19. ftn96

    ftn96 1/2 ton status

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    What about indian summers? [​IMG]

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  20. ftn96

    ftn96 1/2 ton status

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    Doesn't my computer control the timing now? IF so how is all this gonna work? Am I gonna be fighting with the computer and the distributor?

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