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Best way for me to do Vortec heads?

Discussion in 'The Garage' started by kp texan, Apr 10, 2007.

  1. kp texan

    kp texan 1/2 ton status

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    I would like to do a Vortec head, manifold, and mild cam swap on my '88 TBI. I'm trying to figure out if it would be best to go with a set of used Vortec heads and then clean them up with new springs and everything or to just go ahead and buy this kit: http://www.sdparts.com/product/SD8060KIT/VortecHeadKitEdelbrockPerformerIntake.aspx .
    I'm thinking about just going with that kit since I will have piece of mind with brand new heads and I won't have to deal with the time involved in cleaning them up and putting new parts on. I'm also guessing that would be a decent intake manifold since it's designed for 0-5500 rpm. What would you guys recommend? I'm also concerned about the .450" maximum lift but that should be fine for a mild fuel injection cam from Comp Cams or Crane right? I realize that I'll have to go with a bigger TB and some tuning.

    Also, my next question is if you guys have used or know of a good book to go over the basics of building a small block with the tools and procedures involved. I'm pretty sure I have all of the tools I need at home and I'm pretty mechanically inclined and have alot of experience wrenching on things (I work with large diesels in the marine industry for a living).

    Thanks for the help,

    Wes
     
  2. 1977k5

    1977k5 3/4 ton status Vendor

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    Go with the kit, don't go crazy with the cam and don't get a bigger throttle body. I have heard bad things about aftermarket or bored out throttle bodies for Chevy TBI.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Not to start an (inevitable) pissing contest, for that kind of money you MIGHT look for some better heads. AFR, World, etc are going to be more than that, but the quality is better.

    Another option are the pro-topline/RHS and http://www.eqcylinderheads.com/ Pro-toplines could be had for $500/pair at one point, I have heard EQ heads are very cost effective as well.

    Just some more options. Used Vortecs, unless dirt cheap, I'd stay away from, especially if you can't return them if you find they are cracked.
     
  4. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

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    are you keeping the TBI, if so, maybe piecing it together would be better. The pictured manifold is for a carb.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    I think that's the cheapest option to "upgrade" to Vortec heads if keeping TBI...carbed manifold with a TBI adapter bolted to it.
     
  6. 1977k5

    1977k5 3/4 ton status Vendor

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    The AFR heads don't include the intake or gaskets, so that's quite a bit more expensive than the vortecs.

    I agree with your opinion on used vortecs.
     
  7. 1977k5

    1977k5 3/4 ton status Vendor

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    Also, the combustion chambers in the vortec heads are smaller than your stock heads. This will raise your compression ratio and you may need to use higher octane fuel.
     
  8. kp texan

    kp texan 1/2 ton status

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    Yep, I planned on using an adapter and have heard this isn't too bad of a way to go. Just keep in mind that I'm trying to make a very streetable 285-300HP at the crank and not much more. This Blazer will most likely serve DD duty for quite some time and I want good reliable power and a bit more punch than the stock TBI. I had a pretty modded '96 LT4 Corvette that, while really powerful, was quite a bit more of a pain in the arse once I made the changes from stock. I'm not quite ready to do that to an engine again and I want this to have close to stock reliability(although I know any changes will affect reliability to some extent). Oh, and did I mention that I want to do it fairly economically (dont we all, haha) :laugh:.

    Thanks,

    Wes
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    I'm assuming you don't have to be emissions legal? You will throw an EGR code going with Vortecs, and certainly won't be emissions legal. Unless you spend a bunch more money on getting EGR to work. Just other points to ponder if that may affect you.

    Check out EQ and RHS. They sell better heads than the GM castings. I'm not saying I've done your research for you, but they likely have better studs and springs, and they are certainly thicker, which is one of the Vortecs weaknesses. I didn't believe it before, but I've now seen a pair of cracked ones, and heard about enough other ones to realize it isn't an isolated "issue". Keep them cool, probably never be an issue, but that's a very good reason to not go used.
     
  10. kp texan

    kp texan 1/2 ton status

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    Yeah, I'm supposed to have emission equipment onboard but they dont do an emission test. I'm not too worried about the underhood inspection since the inspection stations are pretty leniant and or they don't look very carefully. When I have my new chip burned, can't I just have the EGR and AIR deleted so I won't throw any codes? Well you guys have just confirmed what I've read about the Vortecs cracking so I'm most definitely going to go new.

    Thanks,

    Wes
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    You can have a chip burned to eliminate EGR and AIR, yes. That will prevent any code throwing. Since your engine will need it anyways, it's a no-brainer.

    You might want to be careful with the emissions test...even if they don't look hard, on a clean engine the EGR valve is pretty hard to miss. If it's not on there, you might have an issue. Would suck to do all this work to an engine then find out they change the inspection rules.
     
  12. Thunder

    Thunder 3/4 ton status

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    That is not true. The combustion chamber and valves on vortec and his TBI heads are exactly the same 64 cc 9.2 to one. Also 193 TBI heads are an early fastburn design similar to but not the same as the better Vortec design.
    Only the heavy duty 4 bolt TBI motors have larger 76cc 8.2 to 1 chambers

    KP texan. If all you are after is to make 300 FWHP That is easily attainable with ported stock 193 TBI heads, Cam, headers, intake, and a custom chip.
    it is a far cheaper way to go than a vortec swap and will make more torque than vortecs under 3800 RPM and will easily pass smog. Also with that kit you posted you will have to buy adaptors for your throttle cable and TV cable.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    I gotta see the torque numbers and the chambers you talk about. I've never seen the TBI chamber, so I'm curious as to what they are all about.

    Back to the torque numbers, I've been unable to find any stock Vortec tests back to back with TBI heads. You know of any articles on that?

    According to the GM literature, there were two small block TBI heads used in the trucks, the HD ones must have been 72CC's, as compression on the HD (higher GVW) trucks was still down around 8.5:1. Wouldn't apply to a K5, but something to keep in mind.
     
  14. mr.smartass

    mr.smartass 1 ton status Premium Member

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    When I replaced my motor in my '89 K5, I replaced it with a remanned 4bolt main motor from O'reilly's does this mean I have the larger combustion chambers? Just curious...
     
  15. Thunder

    Thunder 3/4 ton status

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    Acually there are 3 typs of V8 TBI heads .305 had the smallest combustion chamber. The 2 bolt 350s got 64 cc chambers. 4 bolts got the larger 76 cc chamber to lower compression to 8.3 to 1 to deal with detonation under heavy loads. 193 heads are the best to work with to make power. They came on 88 and up 1/2 tons.
    The only way I can explain the combustion chamber on TBI heads is that it is a cross between the old D chambers and Vortecs with the heart shape facing the oppisite way from the vortecs.
    As for numbers i dont have any. And of corse things all depend on the cam you use. but I have ported a couple fo sets of TBI heads with a mild TBI cam and have been very happy with the results. They build an incredible ammount of torque on the bottom end. But because they are swirl ports, even ported they run out of air at 5 K RPM
    I an planning on porting a set this summer mabe I will post a how to article.
    Brian over at TBI chips has a little info on them tho
    This is from his sitehttp://www.tbichips.com/truckmods.htm
    " tow beasts and 4x4 guys. This may come as a shock but I may not recommend changing the heads on those vehicles. Up to 3500 rpms the TBI heads will make pretty much the same power and torque as a good aftermarket set of heads. Its from 3500 rpms on up that the TBI heads start falling off quickly. Well most 4x4s and tow beasts are more concerned about low end torque than having 500hp at 6500 rpms where they can't use that power. The comp cams 12-249-4 cam along with the 1.6 rockers that I mentioned on item 2 will make really good power and torque on a 350 TBI motor up to 4000 rpms. I would then recommend if your building a torque motor that instead of spending the money on a set of better heads that a 383 stroker kit (BALANCED) would be a better choice. While the extra cubes won't significantly add to your horsepower numbers due to the heads not flowing enough air to reach a good high rpm number, the motor will have over 400lbs of torque and still get good gas mileage as TBI heads are rather fuel efficient and a cam that is designed to work well with the combo such as the comp 249 cam and you will have 454 torque with 350 gas mileage. Actually the TBI 454's only made 380lbs of torque which is pathetic for a 454."
     
  16. Thunder

    Thunder 3/4 ton status

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    If the motor was manufactured to GM specs then yes. But who knows what the engine builder did. Only way to tell is to pull the valve covers. There is a number cast in the center of the heads The big 76cc chamber heads number ends in 191. Small 64cc chamber is 193
    The 4 bolt engines were rated at 190 HP, 2 bolt 350 were 210, Torque was pretty much the same.
     
  17. mr.smartass

    mr.smartass 1 ton status Premium Member

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    Horse Dookie! Why did I get the 4bolt main then? Maybe it'll last a little longer... :o
     
  18. Thunder

    Thunder 3/4 ton status

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    Ok I did some searching last night and came up with some numbers, track times and flow, for ported TBI 193 heads. Its from thirdgen.org. I dont really hang out there much because its a car site. But the guy that posted the info ports his heads pretty much the same way I do. He ended up with a Chevy van that runs in the 15s with ported TBI heads Not Bad!!!!!!
    It is a long read but the subject is discussed fairly well both pro and con.
    Here's the link you may have to join the site to see the pics:http://www.thirdgen.org/techboard/tbi/283217-garage-ported-193-s.html

    PS I am not trying to say that ported TBI heads are better than Vortecs or other aftermarket heads.
    But
    They are a very good head for a truck that wont see over 5K RPM. You still maintain good fuel economy and have great torque for half the price of a Vortec swap. Plus they will take far more valve lift than Vortecs.
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

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    Yeah, I've read up on that. With work, the TBI heads can perform well.

    What I'd like to see, and what very few magazines or individuals are willing or capable of doing, is take a setup (like a TBI truck) start with the stock heads, get a baseline. Don't change anything, port heads, *tune the setup*, then re-test. Then go to stock Vortecs, tune, re-test.

    The problem is that claims are made, or performance is shown, but not quantified. Most people (obviously we aren't in this boat) tend to forget the area "under the curve" which is incredibly important getting one of these heavy trucks to move. High peak torque or HP is worthless if it's steep getting there for most truck apps.

    A 2000 5.7 Vortec is 255HP/330lb ft. The 1990 L98 (Camaro) motor was 245HP/345lb ft. (both at a slightly higher RPM than the Vortec motor) The 1989 TBI Camaro was 170HP 4400RPM/255 lb/ft 2400RPM.

    Induction system is obviously a big part of those equations, but there is some info. 300 at the crank is fairly far off considering the above TBI numbers.
     
  20. kp texan

    kp texan 1/2 ton status

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