Register now to get rid of these ads!

what compression hight do i need

Discussion in 'The Hokey Ass Message Board' started by filthyrich1234, Jul 31, 2013.

  1. filthyrich1234
    Joined: Jul 31, 2013
    Posts: 1

    filthyrich1234
    Member

    hey yall im in need of compression hight info ,im buildin a sbc with a 302 crank 3.00 stroke and a283 block with a ,30 over ive got a line on 6.125 rods 4.25 longer than stock any body have pistons for me that will fit in this screamer mouse
     
  2. BOBCRMAN
    Joined: Nov 10, 2005
    Posts: 846

    BOBCRMAN
    Member
    from Holly

    Pistons will have to be custom ordered. Not a good combination. Looking at $600.00 pistons and six week wait.:(
     
  3. mechanic58
    Joined: Mar 21, 2010
    Posts: 681

    mechanic58
    Member

    Um...so you're building a 283 then...

    I'm confused.
     
  4. Well that's a hell of an into, right?
     

  5. mechanic58
    Joined: Mar 21, 2010
    Posts: 681

    mechanic58
    Member

    I don't know about you, but I didn't get a very good first impression. lol
     
  6. saltflats
    Joined: Aug 14, 2007
    Posts: 10,315

    saltflats
    Member
    from Missouri

    So the rods are 4.25 longer.
    Things that make you say Hmmm.
     
  7. in2hotrodz
    Joined: Sep 27, 2010
    Posts: 83

    in2hotrodz
    Member
    from Spiro, OK

    Stock 283 rods are only 1.875 inches long?
     
  8. even with a typo your math is off and that is one long rod for a 3" stroke
     
  9. GOSFAST
    Joined: Jul 4, 2006
    Posts: 254

    GOSFAST
    Member

    We have a 302" on the dyno now, uses a set of 350" Chev "dome" pistons, 14.5 cc's to be exact. With some 6.250" H-beam connecting rods it went right together.

    Don't expect a bunch of power on "pump" with any iron heads, we are actually changing to aluminum heads after the dyno session and upping the C.R. to 10.8!

    (Add) Missed the 283 block above, would definitely change that to a 4.000" bore platform. This is a large-journal build, 1969 "DZ" type.

    Thanks, Gary in N.Y.

    P.S. With this setup you have numerous piston choices! We are using the L2509F/L2510F, TRW's. C.R is at 9.75" with some L/C heads.
     
    Last edited: Aug 1, 2013
  10. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,059

    dreracecar
    Member
    from so-cal

    Id rather go with a shorter rod to decrease dwell time at both ends of the stroke to get that air moving. I run a 6.125 in my 377 but there again I also run a blower
     
  11. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,977

    sunbeam
    Member

    Are the 6.125 rods 2" journal?
     
  12. Ditto on this, with that little stroke your better of with factory length of 5.700 to get the piston off TDC sooner.
     
  13. kracker36
    Joined: Jan 21, 2012
    Posts: 756

    kracker36
    Member

    Is it a "Corvette" engine? BTW, what happens if you take a Nova engine and put it in a Corvette?
     
  14. Mad Mouse
    Joined: Apr 1, 2007
    Posts: 93

    Mad Mouse
    ALLIANCE MEMBER

    Don't understand your combo, you can't get a 6.125 in a sbc standard deck block as the pin ends up in the middle of the rings. You need a .300 tall deck block.
    Good luck
     
  15. fastrnu
    Joined: Feb 26, 2009
    Posts: 739

    fastrnu
    Member
    from shelton,wa

    Someone didnt do their reading before they started typing.!
     
  16. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,059

    dreracecar
    Member
    from so-cal

    I use alu buttons to locate the pins and they are notched to support the oil ring.
     
  17. GOSFAST
    Joined: Jul 4, 2006
    Posts: 254

    GOSFAST
    Member

    Not exactly accurate, as I stated above we have a set of L2509F/L2510F pistons (these are based on the conventional 350" SB platform) with a 6.250" rod and the pins still aren't "through" the oil rings!

    You need to remember he's working with an extremely short stroke, this allows a 1.250" C.H. and no oil rail supports!

    Thanks, Gary in N.Y.

    P.S. Here's a shot of the setup!
     

    Attached Files:

  18. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,977

    sunbeam
    Member

    A 1.38 pin height will not put the pin in the ring package.
     
  19. mechanic58
    Joined: Mar 21, 2010
    Posts: 681

    mechanic58
    Member

    I think this thread has made me dumber. I wish now that I had never clicked on it.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.