I have a 1973 Century GS Stage 1. What is the cam lift & duration?

Discussion in 'Street/strip 400/430/455' started by Warren Jarrett, Dec 20, 2017.

  1. Warren Jarrett

    Warren Jarrett Well-Known Member

    I have a 1973 Century GS Stage 1. I want to choose a new camshaft that is close to the 1973 specs, not the 1970 specs that I see all over the internet. I don't want to lose any of the 1973's incredible low-end torque and low-RPM smoothness. Of course, a little more perceived power might be nice, but it seems to me that low-end torque is more viceral than high-RPM power. No track, no drag racing, I just want a feeling of low-end grunt. Then, when I am on the freeway at 60 mph, a little goose on the pedal will strain my neck and get me up to 110 in an amazingly short time.

    Advice appreciated.

    Can anyone tell me what the original cam lift and duration was?
    I'd like to know the original starting point and think about where to go from there.
     
    Last edited: Dec 20, 2017
  2. gsjohnny1

    gsjohnny1 Well-Known Member

    http://www.nhraracer.com/content/general.asp?articleid=46634&zoneid=132

    pull up 1973. it will list all the engines used in 73. the lift is the only thing nhra cares about. all the other specs are up to the owner. a nhra stg1 spec cam isn't too bad. you could go to a 455 spec cam. it would a little tamer.
    warning; once you start, it will be hard to stop. lol
     
  3. Warren Jarrett

    Warren Jarrett Well-Known Member

    Just curious, why should I care what NHRA cares about? As I wrote, no racing, no drag strip.

    How can I find the duration and overlap specs for the camshaft that I have?
     
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I hate to break this to ya:), but the Stage 1 engines used the same cam from 70-74. The big car 455 cams were a little different. You don't have to take my word for it, just read what the Lead engineer for the Buick big block wrote in this article from the GSCA publication.
    Stage1Cams.jpg

    BTW, it is very possible to have your cake and eat it too. You can easily make 510+ ft. lbs of torque at a nice low RPM and make way more HP than a stock 70 engine, yet have a nice sedate idle. Automotive technology has come a long way in nearly 50 years. The secret is in head flow. With superior head flow, you can use a small cam, and have every bit of what you desire and more.
     
    Warren Jarrett likes this.
  5. Warren Jarrett

    Warren Jarrett Well-Known Member

    Awesome information and advice. Thank you. I suppose that with the Stage 1's larger valves, that is a good start. Is the rest to enlarge and polish intake and exhaust ports in the heads?

    Hmm, I don't even know if I have headers or exhaust manifolds. :(
    Is enlarging and polishing exhaust manifolds almost as good as headers?
     
    Last edited: Dec 20, 2017
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Yes, but the amount of work ($) necessary to even approach the the head flow of an out of the box aluminum Stage 1 head is cost prohibitive. You might as well just buy a set of TA Stage1 SE aluminum heads and get the entry level porting. Using these heads with 10:1 compression and a small cam will easily net you 500 HP. Have a look at this build up with the Stage2 SE aluminum heads and a Stage1 like cam. And this was a 430, 509 HP/540TQ.

    http://www.v8buick.com/index.php?threads/new-buildup-448ci-stg-2-se-hyd-roller-an-mpg-motor.252771/
     
  7. Warren Jarrett

    Warren Jarrett Well-Known Member

    No. no, no. I don't want to get THAT excited. My Century is really junky at this point, just a hand-me-down car that has been ignored for 15 years. I want to have fun with its power, and start making it look nicer, but not max-it-out, or even close.

    My plan is to have a mechanic take-off the front cover and valve covers, inspect the valve timing, the timing chain itself (for tension) and lifters (for mushrooming), maybe just replace the cam to a Team Buick GS-116 or GS-118. Then think about higher performance years in the future, when I can go through the entire engine myself.

    I am very weak now from a recent open-heart surgery, so I have to pay a mechanic to do anything. Hopefully in a year or two, I will feel good enough to do engine work (again) on my own.

    The daughter of this car's previous owner passed-on this information from her father: "the cam chain might be worn-out and the cam is probably flat". These will be addressed, and possibly upgraded. Other obvious problems will be repaired. But that will be it for now.
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Your 73 engine has 8.5:1 compression. You need to stay small on the cam. Why? Read this article on dynamic compression,

    http://www.empirenet.com/pkelley2/DynamicCR.html

    I don't know what a Team Buick GS116 or GS118 cam is. They sound like Poston Enterprises camshafts. Poston has been out of business for many years now. You'll want to look at TA Performance or another source for cams.

    http://www.taperformance.com/

    I would look at these two cams,

    http://www.taperformance.com/proddetail.asp?prod=TA_112-455

    http://www.taperformance.com/proddetail.asp?prod=TA_C110-455

    Or better yet, get a custom cam ground, not that much more.
     
  9. Warren Jarrett

    Warren Jarrett Well-Known Member

    Wonderful help. Thank you.
     
  10. Warren Jarrett

    Warren Jarrett Well-Known Member

    Why is the TA cam higher lift, smaller duration, and closer lobe centers, compared to the stock cam? Or better asked this say, what performance properties will be optimized by each of these more "modern technology" specs?

    TA-112-455: Intake Lift .455, Exhaust Lift .468, Intake Duration 260, Exhaust Duration 262, Lobe Center 112

    Stock 73 Century Stage 1: Intake Lift .410, Exhaust Lift .457, Intake Duration 297, Exhaust Duration 322, Lobe Center 118
     
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Hopefully you read the article I linked for you about Dynamic Compression Ratio, and more importantly, you understood it. Maybe what you need is Camshaft 101. This is from a page of the TA Performance catalog,

    Camshaft101AB.jpg

    BTW, I encourage you to download a copy of the TA catalog. Not only will it show you what is available, but it is chock full of reference and tips. You can download it in pdf form and view it on your computer anytime you like.

    http://www.taperformance.com/

    At the top right side, you will see "Download the TA Catalog". Click on it.

    http://www.taperformance.com/catalog.htm
     
  12. gsjohnny1

    gsjohnny1 Well-Known Member

    if you READ the info on nhra, it tells you what the cam lift is, AND THE INFO IS FROM BUICK, if you wanted to do a blueprinted camshaft for your car. most all other camshafts made are not copied from the nhra/buick list.
    the info from manner is a lot different than the info from the nhra/buick info. the nhra stock buicks wouldn't go that fast if they used those specs.
     
  13. Warren Jarrett

    Warren Jarrett Well-Known Member

  14. Warren Jarrett

    Warren Jarrett Well-Known Member

    Next question about my project please. Just to remind, this 1973 Buick Century GS Stage 1 has been sitting for more than 15 years. A mechanic cleaned out the fuel tank, and the car started right up, but ran poorly. The cams are flat and the timing chain is loose, so those are getting replaced. I am also having him replace the water pump and oil pump.

    The mechanic suggests upgrading the points ignition distributor, too. I am thinking I want to install a stock GM HEI distributor, the 4-pin type, that was used in Buicks between 1974 and 1977. Does anyone have a different suggestion?

    And, what about the Buick HEI distributors I see on Ebay, for under $115 to $160? Should I spend the extra money and get a MSD (about $400)?
     
    Last edited: Jan 3, 2018
  15. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Have Ken at Everyday Performance recurve and rebuild your points distributor. You won't be sorry.
     

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