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Too much cam?

Discussion in 'The Hokey Ass Message Board' started by JMel, Jan 14, 2013.

  1. JMel, if you want to be safe, you can chose the Comp High Energy 268. Easy install, good all around grind, you should be very pleased with the results with your current combo and no real need to upgrade anything else. Always better to undercam than over, all the best, TR.
  2. Jimmy2car
    Joined: Nov 26, 2003
    Posts: 1,707

    from No. Cal

    Get rid of that axle ratio. Geeeze
  3. von Dyck
    Joined: Apr 12, 2007
    Posts: 678

    von Dyck

    CompCam 268 Extreme on 1.6 rockers, 350 (.030 over bore), 194 Heads over top of cast jobber pistons computes to a 10:1 compression, premium fuel, 625 Edelbrock, 1800 stall in TH350 into 3.08:1 diff. This in a 2600# Nova and is quite manageable on street or highway. The heads cc'd at 65 cc.

    I have and read numerous "How to build SBC engine" books. One of the best IMHO is by David Vizard, "How to build Max-Performance Chevy Small-blocks on a Budget". Chapter 7 on "Cams and Valvetrains" is the most comprehensive information I've read anywhere and is worth the price of the book alone. Chapter 12 has 10 recipes for hot engine builds from mild to hairy. From SA Design #57 copywrite2009 160 pages
  4. Moedog07
    Joined: Apr 11, 2011
    Posts: 188


    Comp High Energy 268 is a good choice for 327 - 350 CID small block Chevys. :D You will Know it's not stock but should pull good with those gears. The weight of the car will balance with those numerically low gears.
  5. Thank you , I chose that over the EXTREME mentioned above simply because of the intake manifiold. Single 4 barrel manifold I would have gone Extreme 268 but not with the Tri-power set up, TR
  6. Dan in Pasadena
    Joined: Sep 11, 2009
    Posts: 860

    Dan in Pasadena

    Not wanting to hijack but reading this thread with some interest.

    What do you guys think of the Comp Cams 268 in an early 283 with camel hump heads (1.94's I THINK - bought it this way), an Edelbrock Performer intake, Quadrajet, and headers? Thee cam in it is very rumpety-rump and gives me too little vacuum to run a brake booster. I'd need to correct that, have a bit of low end torque, don't truly care about impressing anyone with the idle. No, I don't know the rearend ratio. Its got a 350Th in it if that helps. Thanks, Dan
  7. davidh73750
    Joined: Apr 21, 2009
    Posts: 1,563


    I agree with you all of you on that old comp cam 268(for any 283-400 for that matter). Hard to beat and still driveable. Back in HS day I saw many cars/trucks beat with this old cam profile , 4bbl, performer intake. while the guys were waiting for their 300+duration cam to kick in at 3grand with their 2:73 gears the 268 cam'd vehicle was gone. Crane has one almost identical, 266 450 lift and I think summit has it in a single cam profile.
    Will we see you heading to Lonestar in a few months??
    Last edited: Jan 14, 2013
  8. I only posted the specks of the cam as an example of lift and duration although OP did state that he is about to purchase a 350 short block but did not indicate what style it is.
  9. davidh73750
    Joined: Apr 21, 2009
    Posts: 1,563


    that cam will be just fine known a few with that cam in a 283 . 2010 Had a 266 crane almost identical to that cam in my 68 biscayne with a 283, 305 heads, performer rpm intake 600 edelbrock. got +20mpg on hwy
  10. Hotrodbuilderny
    Joined: Mar 20, 2009
    Posts: 1,646


    Does anyone read these questions? He said he is building a 350.
  11. Home Brew
    Joined: Oct 12, 2007
    Posts: 97

    Home Brew

    The .298 is lift at the cam. Using 1.5 rockers ( normal Chevy ) the valve lift is .447.
  12. Russco
    Joined: Nov 27, 2005
    Posts: 4,167

    from Central IL

    Did you? Dan in Pasadena asked about the same cam (Comp 268) in a 283.
  13. Jay Tyrrell
    Joined: Dec 9, 2007
    Posts: 1,631

    Jay Tyrrell

    Check out Comp Cam Part Number 12-246-3. With all of your specs of that new 350 ci motor you will really turn that coupe on big time! Check it man!
  14. Hotrodbuilderny
    Joined: Mar 20, 2009
    Posts: 1,646


    Wasn't talking about Dan in Pasedena,he wasn't the original person to ask the question, who they were replying to.The people I was refering to were the ones who said it was to much for his 305,and Dan in Pasedena didn't mention gear ratio,and the original poster was not asking about a Comp 268 cam with 290 degrees duration that would be a Comp 290 cam.
    Last edited: Jan 14, 2013
  15. rlsteel
    Joined: Apr 10, 2005
    Posts: 419


    a 3.50 -3.70 gear will fix you problems RLS
  16. This is a quick study to know how engine parts specs/convertor and trans specs/rearend gear ratio/tire size all work together. It's assumed that the car will be driven in the "normal" street manner, when the engine will rarely exceed 2500 RPM on a regular basis.
    A basic street engine with normal low rpm range will need to have a cam that has between 215 and 225 degrees cam duration @ .050" lift, 112 to 116 degrees lobe center separation, and lobe profile that compliments the combination. Compression with iron heads can get into the 9.5:1 range if the car isn't too heavy and if ignition advance needs to be played with based on gas octane rating. A stock convertor is usually good with a streetable cam. Rearend gear needs to be chosen based on tire height/rotations per mile of tire compared to direct or overdrive transmission ratio.
    Engine RPMs to gear ratio to tire speed decides a bunch.
    Study a cam spec catalog. Compare computer car cam stuff to 4x4 and torque cam specs. Compare again to high RPM drag and sustained RPM asphalt car cam specs. Knowledge is available. It's up to us to apply it correctly.
  17. ottoman
    Joined: May 4, 2008
    Posts: 293

    from Wisconsin

    Go to and download the cam program... input your info and it gives you a selection of recommended cams for your application.
    I send guys there that dont know much about cams or dont want to listen.. makes em feel they picked out there own cam. If your honest with your info it will get you the right grind or pretty close at least.
  18. fiveohnick2932
    Joined: Mar 29, 2006
    Posts: 889

    from Napa, Ca.

    why have you chosen to run a 2400 stall converter without choosing a cam yet. 3.08 gears and a 1900 lbs car..... hummmm. Why dont you put a "mild cam" in there? Any cam with 290s advertised duration is a wild cam, more on the "strip" end of street/strip. For your cam I would stay between 260-280 advertised duration, that's some place between 214-230 @.050. The higher lift the more money you have to spend on springs and all that crap so things will hold up with the high lift.

    Comp Cams 270 magnum cam is a great cam. 224 deg duration @ .050 270 advertised with a 110 LSA. you can use it with most of your stock stuff including the converter. Another cool cam is the Isky 264 mega cam, off the top of my head I think its 214 duration @ .050 and 264 advertised, .450 lift and 108 LSA. The 108 LSA gives that cam a little more sound than normal. The .450 lift will be easy on parts and last a long time.
  19. Lots of sound advise here about cams. I'm in the group that would recommend the 268 cam. Those rear gears are a problem in your combination though. If the convertor actually stalls at 2500, you'll be driving down the highway with the convertor slipping and that will cause overheating (or you'll have to drive 80- maybe try that as an excuse when you get pulled over "my torque convertor made me do it officer")
    Another point- lumpy sounding cams don't equal good, torquey street cams.
    Stick around 220 or 230 (at .50) and lift between 470-500, love separation 112 or so. Close seperate on is for higher rpm power (and choppy idle).
  20. Sheep Dip
    Joined: Dec 29, 2010
    Posts: 1,572

    Sheep Dip
    from Central Ca

    For basic good reading knowledge to help understand cams and other performance componets I recommend "Smokey Yunick's Power Secrets"
  21. KeithDyer
    Joined: Mar 26, 2007
    Posts: 193


    /\ /\ /\ /\ What he said!!! /\ /\ /\ /\ Pretty sure that the "151" is the old 350 horse 327 hydraulic grind. Great street grind, but remember a couple of things:

    The motors these came out in were a little higher static compression, that is how they worked well with that lobe separation, plus had some good vacuum. Not be afraid to advance it a little bit.

    Also, not forget to use something like Brad Penn oil or you new cam will not make it very long.

    Take care, K
  22. 01Dudley
    Joined: Jun 1, 2010
    Posts: 90


    It is really this difficult to build a SBC these days? We will all have opinions as to what will work best and why. Is your machine shop cleaning the heads up at all? Is anything gasket matched? Are you replacing the valve springs(I have assumed you are)? Spend the buck and get roller rockers(either aluminum or steel / it is a friction thing). Call Lunati or Comp and ask them about that cam or a similar cam with your 3duece setup, the stall and the gear. Don't leave out details! Tell them compression, what type of gas you watn to run, how you intend to drive it etc. I bet the worst item in your set up will be the gear. Change it to a 3:73 or 3:42.
  23. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,128


    Don are you sure about that 290deg @ .050 thing that is one big number.
  24. JMel
    Joined: Jun 18, 2011
    Posts: 199


    Thanks for everybodies input. I'm on a budget....don't have a couple hundred more for another cam - so am now between just keeping the thumper and seeing if it comes alive with the higher compression and larger displacement, or use a Melling 22210 that I ordered - which apparently is a little more aggressive than the 22200. Got it for $30, and was told by Melling that it should be ok with a 2400 stall, although it still may be a little much stall - he suggested I try it out.

    As for why I have a 2400 stall before the cam? I already have a running car and engine, and the 2400 stall was needed in the 305 with that poser cam....errr, Thumper cam. Have had multiple people suggest that the cam should waken up in the new motor and to try it out. I expect the block back tomorrow...will make a decision on which of the two cams I'll use when i pull the 305 out of the roadster. Constantly go back and forth between the thumper and just putting the Melling cam in. I'll likely have more power out of the Melling 22210 - so will likely go with that and hope its not overkill in a 1900 lb car.

    The heads will be rebuilt - ordered new springs, new valves, new lifters, new pushrods, new valve locks, and new retainers.

    Do however have to switch to an electric fuel pump now, and need to buy a new flywheel, and see if the oil pan off the core can be salvaged as the flywheel and pan off my 305 won't fit up to this block. Not sure if timing chain cover will fit up...although I assume it will. I imagine I'm going to get nickle and dimed to death once I actually start putting everythign together - just like I did when I built the car. Get all of the expensive shit bought and set aside and think I'm on easy street, not realizing the thousand+ dollars I need in little shit that I didn't think about.

    Have some upgrades on the short list...but it was all I could do to convince the wife to let me spend the money I'm spending. Another cam that does more what I want to do, as well as rollers is on the list for the next time I can throw a little money at the car. Although once I get this done, i need to start thinking about rebuilding the engine in the '51 Chevy, and that needs to be completely rewired as well.

    Perhaps 2 old cars at the same time wasn't wisest choice I ever made. :)
  25. mustangsix
    Joined: Mar 7, 2005
    Posts: 1,297


    The specs for that (and many other) 22200 Melling cam is on the site.

    223 @ .050 is not that big a cam but I've never used one so can't speak to the idle, vacuum, or power curve.

    But with that gear and converter, I think I would go with something like a 10120701 Lunati Voodoo for a street driven car. With only 213/219 @ .050 and .454.468 lift on a 112 lobe center, it'll idle nice and pull a 1900 lb car like a rocket with 3.08 gears. It'll be a good match for a 2400 rpm converter in that lightweight car and the power will be right in the range where it operates on the street. Still should pull to 6000 easy, though.
  26. JMel
    Joined: Jun 18, 2011
    Posts: 199


    Oh....and different gears and maybe a new tranny is on the short list too. Coming soon to a thread near you - what tranny should I get to replace my TH350. :)

    We'll save that one for later. Haha
  27. Fixed it, meant 290° at zero, 234° at .050
  28. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,304

    from USA

    nope its mostly
    bragin that i know more than u:cool:

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