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L79 Cam in a 400

Discussion in 'The Hokey Ass Message Board' started by 37_chevy, Sep 27, 2012.

  1. 37_chevy
    Joined: Aug 8, 2010
    Posts: 168

    from Nebraska

    OK, I searched, a lot and found a lot of posts about the L79 cam, but they were mostly about 327's or 350's.
    I'm building a 400 for a 56 Chevy Gasser. The machine shop says we should end up with 9.5:1 compression. Using the heads with the 1.94 intake valves and the 76cc chambers. Will be bored .030 over. Gonna run a 4 speed.
    I want to be able to run power brakes and will have disc brakes on the front. Car will be street driven, but want to be able to run respectable times at events like the HAMB Drags.

    I've been looking at the Comp Cams website and I like the looks of the L79 cam they make. Anybody got a better suggestion?

  2. Deuces
    Joined: Nov 3, 2009
    Posts: 19,583

    from Michigan

    Go for it!!..
    Also, make sure you get the right flywheel for the manual trans setup!!
    400 small blocks are externally(sp) balanced motors...
  3. 37_chevy
    Joined: Aug 8, 2010
    Posts: 168

    from Nebraska

    Yup, got the flywheel. I've used this motor before.
  4. Is the L79 the 350 hp 327 cam? If so that is actually going to be pretty mild in the 400. I ran one of those way back 30 years ago in a 350 and i thought it was kind of grandma-ish cam then. A 400 would be even tamer. I would go bigger and a more modern grind if you really want performance. The more modern cam will have increased lift and greater area under the curve. The 350/327 cam is like 224 degrees duration at 0.447 lift if my memory is right. I would go up to 230-235 duration and lift 0.480-0.500 range for better performance. The 400 will keep the vacuum power brakes working, although i bet you could do manual brakes and be fine. Just my opinion, worth what it costs.

  5. Canuck
    Joined: Jan 4, 2002
    Posts: 1,064


    Like 38Chevy says, it will be a mild cam in a 400.

    Currently running one in a 406 with World Heads and 10/1, Hi stall on a 700R4. Very light lope. Does make a good every day driver cam to fight your way through down town traffic with decent gas mileage as a added benifit. Power brakes definately not a problem.

    Doing it again I think I would go a bit more agressive. This was a recomendation by my machinest.

  6. greg32
    Joined: Jun 21, 2007
    Posts: 2,073

    from Indiana

    Needs more cam, look at thumper or motha thumper for a gasser kinda car, you'll like it.
  7. Yep. Also consider the Lunati Voodoo 60103. Good torque and horsepower, you can run power brakes, and has a nice rumpity idle. A buddy has one in a 350, along with a 3" exhaust, and it sounds awesome.

    A Gasser has to sound racey. No wimpy, silent cams!
  8. 37_chevy
    Joined: Aug 8, 2010
    Posts: 168

    from Nebraska

    "A Gasser has to sound racey. No wimpy, silent cams!"
    I totally agree!

    Here are some more recommended by Comp. Any thoughts on these?

    XE274H - Centerline 106 degrees
    Duration Int/Exh 274/286
    Dur. @ .050 230/236
    Lift .490/.490

    XE284H - Centerline 106 degrees
    Duration Int/Exh 284/296
    Dur @ .050 240/246
    Lift .507/.510

    Mutha' Thumper 287TH7
    Duration Int/Exh 287/305
    Dur. @ .050 235/249
    Lift .489/.476

    I'll take a look at the Lunati too.

    Thanks guys. I didn't ask because I wanted to hear I was right. I ask because I wanted to know!
  9. 37, that cam will be a joke in a 30 over 400 in a car the size and weight of a 55.

    Ask yourself this, can you afford a upgrade to a retro-fit set of hydraulic rollers? This will open up many new and better/efficient cam profiles, PLUS the advantages of roller lifters.
  10. Something to consider, that too many people don't. The L79 was orignally designed for the piston dwell and piston speed of a 3.250 stroke (ie, valve opening and closing sequences). If you use that valve timing on a 3.750 stroke (1/2" more) you and your 400 will be left "wanting", not to mention that the L79 is to small period! The Thumpers and or Comp's XE series work very well for a "one size fits all" line of "on the shelf" cams. If you really want to do it right, call Scott at Competiton Components, (517)719-5935 and have a cam custom ground for yours and your engines particular needs.
  11. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,579


    Just because it is a gasser, be careful that you don't over cam it and make it un-drivable, just so it sounds right. You failed to mention your gear ratio and tire height, that will make a difference in your RPM range.

    Your 9.5 static compression ratio will drop (to a lower dynamic ratio) based upon your cam choice. I used several of the on-line calculators to choose my cam for my .040 over 400. My goal was different (good mileage/low rpm). From what I've read, the best street cam for your setup is one of the Comp Cams extreem 4x4 camshafts. In the 400, they provide a huge smooth torque curve with your compression and heads, but it might not sound lumpy.
  12. Danny G
    Joined: Aug 1, 2006
    Posts: 399

    Danny G

    I have the xe274 in mym55mand it runs and sounds great
  13. 37_chevy
    Joined: Aug 8, 2010
    Posts: 168

    from Nebraska

    Back up for the evening crowd. :)
  14. You can download the Comp Cams cam selector program and indicate what you want the car to do. It will give you different scenarios and ask you different questions about what your trying to accomplish. Interesting program...
  15. dad-bud
    Joined: Aug 22, 2009
    Posts: 3,884


    I agree with kscarguy - too much cam is worse than too little - for sure!
    Your 400 will tame the L79 a bit but don't go way too big trying to compensate.
    A roller cam is a good idea if the bucks stretch.
    Good luck with it.
  16. Grumbler
    Joined: Mar 2, 2009
    Posts: 358


    The online Comp Cams selector is good. I filled it out and submitted when I was loking for a new cam for my 455 olds, they got back to me in a timely manner, asked a couple of futher questions for clarification and made a reccomendation. I went with it and it does everything I was looking for, no surprises.
  17. tjet
    Joined: Mar 16, 2009
    Posts: 1,272

    1. Early Hemi Tech

    If you want a nice vintage exhaust note, install a Comp Cams Magnum 280H. It is a single pattern cam, & it's has more of a classic "rhythmic" sound than the dual pattern Xtreme energy cams. That 400 will like the 230 deg duration
  18. a1txtech
    Joined: Dec 20, 2012
    Posts: 1

    from tx

    I had an L79 cam in my '67 ss chevelle with the 400 completely stock less the forged stock compression pistons, toker intake and headers. It did 11.2 quarter with 4.11 posi and 9'' slicks. Running a super shifting 400 thm. Not too bad I guess for the year of 1980.
  19. 53sled
    Joined: Jul 5, 2005
    Posts: 5,818

    from KCMO

    You don't want to bleed off too much pressure or limit flow with an off the shelf grind for a smaller engine. I ran a cheapie hydraulic melling .496 lift (memory is hazy) on a 377 destroked 400 with power brakes, 86 monte. But it was 10.7 comp.
  20. New members are supposed to do an intro, the information is at the top of the page. " New to the HAMB, Introduce yourself here ". Also, this forum is for 1965 and older vehicles. The thread you brought up is 3 month's old, and apparantly the O/P or original poster isn't even interested anymore. Your vehicle is what we refer to as O/T or Off Topic.

    This was 3 month's ago?
  21. 47.Poncho
    Joined: Nov 16, 2010
    Posts: 68


    Dont be afraid to go big on the cam. The big 400's eat them up. I have a 406, 4 speed with stock bottom end(dish pistons), cammel humps, single plain intake, 800 holley. I put in a old solid Chad Herbert with .550 .530 lift, 112` lobe seperation and 255` 260` duration. With the 4 speed you don't have to worry about making it idle so low like an auto so put lots of cam in it if you want to make some power. If I built my engine again I would put even a bigger one in. Mine idle's nice at 1200 rpm. Even with the single plain intake, low rpm still pulls hard because it makes so much torq. fantastic engine if you ask me.
  22. slammed
    Joined: Jun 10, 2004
    Posts: 8,151


    My God dude, a cam selection for this is slam dunk with all the information at each manufacture web site. That present cam is way to old and small for this motor.
  23. 70L34
    Joined: Aug 27, 2005
    Posts: 254

    from Detroit

    That must be some sort of record for an L79 cam. Come on man....
  24. 37_chevy
    Joined: Aug 8, 2010
    Posts: 168

    from Nebraska

    I am the original poster of this thread. I don't know how it came back to the top, but it wasn't me. BTW, I called Comp Cams and they gave me the info I needed.
    Havn't built the motor yet, so I don't know the result.
  25. propwash
    Joined: Jul 25, 2005
    Posts: 3,858

    from Las Vegas

    It came back to the top because Mr a1txtech newbie wanted to spin a yarn about his amazing off topic Chevelle he wants us to be impressed with before he does an intro.

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