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Vortec or AFR Heads?

Discussion in 'The Garage' started by Shawn, Oct 25, 2005.

  1. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Okay, I'm now leaning towards the AFR heads. I already have a performer manifold that will fit my 400 SBC with standard SBC heads. If I got the Vortec's they would need to be modified to accept more cam lift and sdpc has them already done for a package price since I would need a Vortec manifold too.

    I have a guy selling some new AFR's for about $1000 and the Vortec head kits runs $900.

    What do you guys think?


    http://www.sdpc2000.com/catalog/217...ortec-Head-Kit-Edelbrock-Performer-Intake.htm
    Our Vortec cylinder head kit provides you with everything you need to install the new Vortec heads on your vehicle. The following kit includes assembled Vortec heads, head gaskets, GM head bolts, GM stamped steel rocker arms, intake manifold, intake gaskets, 12 point intake bolts and additional required components as stated. This kit features our upgraded Vortec heads which have been modified to accept our high performance Z28 valve springs with lightweight LT4 retainers. This produces a high reving cylinder head that can handle up to 0.525" lift hydraulic camshafts. An Edelbrock Vortec Performer intake manifold is matched with this kit for optimum performance.



    http://www.airflowresearch.com/pages/195sbc_sh.htm
    The AFR Emissions Legal (versions from 1969-94 with heat riser, CARB EO #D-250-2), 195cc intake port small block Chevy cylinder heads are available in your choice of straight or L98 angle plug versions. These heads feature a 74cc or 68cc combustion chamber with a 64cc exhaust port and a 3/4” thick head deck (ideal for nitrous or blower applications). The 68cc chambers are designed for flat top or dished pistons; domed pistons will require additional machining. Standard valves are 2.020 intake and 1.600 exhaust with AFR’s hardened ductile iron interlocking valve seats. The exceptional flow characteristics, ideal operating range of 2000 rpm to 6500 rpm, 23º valve angle, and standard valve spacing make this the perfect street head for 350 cid to 400 cid engines from 1955-86. Available for 1987 to present engines with center bolt valve covers and 2 center intake bolts at 72º angle. No special parts are required.



    http://www.chevyhiperformance.com/techarticles/83138/index1.html
     
    Last edited: Oct 25, 2005
  2. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    I've heard nothing but good things about AFRs...

    In fact, it seems like the only reason people don't ALWAYS buy them is due to economics (AFRs seems to also be the MOST expensive option too!)

    Their flow numbers seem great....and have always been backed up by independent magazine testing, so it's not just marketing hype. The observation about "flow under the curve" vs. "peak flow" makes a lot of sense to me as well... a big, meaty flow curve would sure seem a lot more sensible on a street car....where a pure "full throttle" drag car might be able to get away with a high peak flow-type head....and save a few bucks in the process.
     
  3. theperfectgarage

    theperfectgarage 1/2 ton status

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    Right on, great research you,ve done. If I read right, the vortec kit did not come with the vortec performer intake. there both great choices but seeing as you have the old style intake, go with the afr's. With these choices I dont see how you could lose.
     
  4. sled_dog

    sled_dog 1 ton status

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    I have heard before(who knows if its believable) that the people at AFR helped GM design the Vortec heads. AFR uses the same combustion chamber design as Vortec heads from what I've always been told.

    Like Greg said, if I could afford aftermarket heads, it would be AFR for me. ANd like you noted, all added up they come out to relatively similar pricing.
     
  5. Shawn

    Shawn 1/2 ton status Premium Member Author

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    I found a place selling AFR's for about $1200 brand new with free shipping. Its not much more than some of the other heads out there.

    Its also tempting just to purchase the standard Vortecs (with no mods) and run a smaller cam. The heads are less then $500 new or $250-300 on ebay (used). Still need a special manifold though ($200).
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    We discussed this a bit before, aren't the Torquers (II?) using a fast burn chamber now, and a fair bit less expensive than the AFR's, something like $800/pr?

    They seemed to be a pretty good piece all things considered.
     
  7. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Yeah, $800 at Summit. They're #12 on the list for flow. I wonder if thats the newer design that they tested.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Yep, I was wrong, thinking of the sportsman II's. From Worlds page, the torquers are still crappy chambers, Sportsmans are fast burn. And they are ranked about middle of the pack in your first post. :)

    For me, when looking at Vortecs, flow and chamber are great (which is why they are good heads) but all the other issues are what turn me off on them.
     
  9. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Yeah, too bad GM didn't make them with better springs that could take more lift. other than that, a really NICE head.

    Found this article which is part II of my 400 sbc build up:

    http://airflowresearch.com/articles/article39/A-P1.htm
    [​IMG]
     
  10. beater_k20

    beater_k20 Banned

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    for $1000, i'd go with the AFRs, not only do you get a better flowing set of heads, but you get aluminum heads as well. from your previous posts, i can tell you like performance. while Vortecs are decent performing heads, the AFRs are much better in several areas. you will be much happier with them.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes if you can afford them, no argument here that AFR's are the way to go.

    For just a couple hundred more per pair, you can't really go wrong.

    I'd certainly trade a bit of low end for some more topend. If you always kept the RPM's down then the low end numbers would the only thing important, but if you like the throttle, you need some top end.
     
  12. sled_dog

    sled_dog 1 ton status

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    Not sure what you feel the advantage of an aluminum head is, weight is about the only real existing advantage...

    If they made AFRs in a steel head, man that would be sweet.
     
  13. beater_k20

    beater_k20 Banned

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    lightweight, better heat dissipation, which means less hot spots in the combustion chamber, and less chance of detonation.
     
  14. Shawn

    Shawn 1/2 ton status Premium Member Author

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    I'm with you. I like both but I find myself in the upper RPM quite often... :)

    The question now is 180's or 190's. The guy I know has 190 cc heads for a good deal. I'm wondering if 190cc would be too much.

    I read many times you can run more compression with alum.
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    I would think when building a 400, the larger runners can't be a bad thing. Especially when talking upper end.

    While the article you mention places some of the heads down compared to the Vortec, they did average those across .3-.400 lift numbers. Again talking stock to stock, the Vortecs are 1.94/1.5's, the Sportsmans (for instance) are 2.02/1.6. Valve size isn't everything, but a larger engine at higher RPM's is going to see at least some benefit from the larger valves. At least they won't be a choke point. No idea what the AFR's run.

    Aluminum's only real advantage is weight savings, along with perhaps ease of repair, but on a non-racing engine, I don't think the repair aspect is very much a factor.

    Aluminum heads can/need to run more compression because they do bleed heat so well. Heat=power, which is why iron heads (identical construction) in controlled testing make more power than aluminum. I think that's a *fairly* new realization, at least in the aftermarket, because you started to see actual comparisons iron to AL in heads, and the consensus eventually seemed to be that iron heads make more power. But if you up the compression in aluminum heads at least in a 1/4 mile car, you will probably break even between the two.

    Personally, weight reduction is never a bad thing. On these trucks though, the weight savings of aluminum heads alone is probably pretty negligible. Still cool though. :)

    Now couple those heads with an AL engine block and you are on to something lol.
     
  16. sled_dog

    sled_dog 1 ton status

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    The general consensus is 1 point of compression up to even out the power lost with aluminum heads. That was my point, iron vs aluminum, iron wins. A polished Iron combustion chamber will be better with less hotspotting or detonation issues.

    The best place to remove weight in an engine is of course rotating assembly, but like said, lost weight is lost weight. In a truck of any kind(except all out drag or race) I'd run aluminum heads.
     
  17. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Here's a good article on iron vs alloy

    http://chevyhiperformance.com/techarticles/83858/

    Wouldn't 1 point of more compression give you more than 5 lb-ft of torque?
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    Again, I think that is based on the heat lost during combustion in AL heads....same compression, EXACT same heads, the iron head is making more power. Bump the AL compression up, and what they are saying is that on the same engine, the AL heads would be somewhere around 5ft lbs better than the irons.

    The gain from compression IS higher than that 5ft lbs, BUT since the AL starts at a lower number than iron in the first place, the NET gain in power is slight.
     
  19. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Another thing to consider is fuel.

    http://www.diabolicalperformance.com/hotrodoctane.html
    It would be nice to run the standard grade of fuel on my 400 and not have to pay for the high octane stuff at the pump while running 10:1.
     
  20. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, again, it comes down to aluminum saving you weight.

    If 9:1 on iron heads (fast burn chambers are going to let you run 87 at that compression easily) make as much power as 10:1 AL heads, there is no difference except that you have more compression.
     

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