1972 LS3 402 CI Specification Questions

Discussion in 'Engine Topic' started by GRIFFBL, Mar 18, 2018.

  1. GRIFFBL

    GRIFFBL New Member

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    Gents-

    I am eyeing a 1972 396 (402) Camaro that is bone stock. What options do I have in terms of bolt on aluminum heads? I want to shave weight up front, and that alone with an aluminum intake will shave a bunch. I am guessing maybe more than 40 LBS combined. But I do not know what stock pistons came in a 1972 402? Are they domed or flat tops? The short block is solid, so I was looking for some heads that might raise the compression slightly, save weight, while flowing better. But I don't know where to start in terms of making sure I have good piston to head clearance. From what I have read, stock 1972 heads were either 105 or 110 cc, but their shape can be very different on an aftermarket head. I would rather simply change heads and intake, (and any necessary valve train items) as I want to leave the crank and pistons alone. Any suggestions much appreciated!
     
  2. Z27LS3

    Z27LS3 Veteran Member

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    is this a numbers matching bone stock engine or just a replacement engine ?
    if it is really the original engine to the car I would "if mine" pull it and set aside, then
    get a different engine in there. 72 was the last run of big block camaros and there
    were less than a thousand made.
     
  3. GRIFFBL

    GRIFFBL New Member

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    Thanks. While the engine is completely original, and numbers matching, the car is not THAT valuable, in my opinion only. You would never get your money out of procuring another engine, and pulling the original, storing it, installing a crate motor etc. I simply want to change the heads if possible, and enjoy it, and "tag and bag" the original heads etc. The original heads could always be re-installed if necessary for another owner. I just need to know if this engine came with pop up or flat top pistons, and if the valves and spark plug will clear, so as to safely bump up the performance and Compression ratio a bit via a head change while lightening the car's front end at the same time.
     
    Last edited: Mar 19, 2018
  4. Rich Schmidt

    Rich Schmidt Veteran Member

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    A 1972 big block car is valuable. It is the last year for the big block and a shortened year because of the strike. It is the 2nd most valuable 2nd gen ever made only topped by the 1970 L-78 cars.
     
  5. Z28PILOT

    Z28PILOT Veteran Member Lifetime Gold Member

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    Hi ,
    i won't comment on the value or rarity issue . i understand where you are coming from as a owner of an LS4 low compression from same era wanting to use the original engine . i don't want a chromed up blower engine with 800 hp .
    As corvettes are more common and less valuable , you can find more comments threads on the Corvette Forum dealing with smog hopp up s for late LS Mark IV . i suspect the Chevelle threads address this . Its not so rare and high esteem in those forums. Seems slapping aset of 1970 LS5 heads maybe common to raise the compression. They will bolt up with all the other stock stuff and keep the appearance . Some guy s may used the LS5 cam too. And some add flat topped pistons . I think yours are notched . You can use a Chevy by the Numbers book. To compare GM parts , pistons, heads , carbs , etc . Im still stock , but if i rebuild I ll go to 1970 spec. , and call it good .
     
  6. PaulC

    PaulC Member

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    Well, here's my 2¢. I have a '71 SS/RS LS3 and at one time had the same thought. In '71 GM switched to a oval port "open-chamber style" head and taper seat plugs. The chamber was open more than a true open chamber Mark IV head giving a 8.5:1 compression ratio, so my thinking was slap a set of stock closed chamber heads on and presto, 10.25:1 compression with the stock domed pistons. It ran fine, just no noticeable performance improvement, probably because the open chamber heads breathed better even though they were a "smog" head.
     
  7. GRIFFBL

    GRIFFBL New Member

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    Thanks for the input Gents. I was thinking an aluminum aftermarket head so as to save weight, flow a bit better, and bump the compression a bit all at the same time.

    Best,

    Brad
     
  8. Rich Schmidt

    Rich Schmidt Veteran Member

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    The Edelbrock SS 454 heads have 100 cc chambers. They may require a little bit of grinding if you have domed pistons.
     
  9. badazz81z28

    badazz81z28 Veteran Member

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    I never did understand this mentality....Save it for what??? What are you going to do with the car? If one was really concerned about it, keep it original...restore it and keep in the garage for the next 50 years. In case anyone forgot we have an expiration date...Are you saving the car for your grandkids or do you want to enjoy it?

    I don't care how much my 1970 Camaro is worth or what it will be worth. I modded the crap out of it because I wanted the cool looks and still wanted it to be somewhat modern and fast. We place too many things on pedestals for other people to enjoy them decades down the road or to make some cash (which most of them do). Ever watch GMG? Seems all the cars they sell off for cash are left by their deceased family members. Forget all that! Do what you want to do with the car and ENJOY IT!

    With that engine you can get a nice set of aluminum heads just about anywhere. It will surely save you a ton of weight. https://www.ebay.com/sch/i.html?_fr...m+heads.TRS0&_nkw=BBC+aluminum+heads&_sacat=0
     
  10. Rich Schmidt

    Rich Schmidt Veteran Member

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    Some people will say that we are just the caretakers of these classic cars. They believe that they belong in a museum for future generations to admire. Kind of like paying millions for a painting even if you don't like it just because everyone else says it is worth it.
     

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