Results 1 to 7 of 7

Thread: 454 BBC Piston Question on Closed Chamber

  1. #1
    TJS
    Ok I have an uncut 1970 LS-6 motor with closed chamber square port heads. The heads have been CC'd at 108cc. They were 110 but milled a little. I want to keep a comp. ratio of about 10:1 (not much higher). I want forged full floating. I have searched summit and Flatlander and when I think that something looks good until I click on the details and it states (open chamber heads). I think I read somewhere you can use closed chamber pistons on open chamber heads but cannot use open chamber pistons on closed chamber heads. Correct me if I am wrong.
    The block will be cut .030 over and swinging a stock forged crank with eagle H-beam rods. Please give ideas and part numbers.
    Thanks.
    T.J.

  2. #2
    Jeremy1Kanobe
    For domed pistons you are correct witht the idea that closed chamber pistons can be used in open chamber heads but not vice-versa. The chamber shapes are different. When using a flat top or dished piston the pistons will work with either head. The valves are in the same location between the open and closed models.

  3. #3
    oldbuck40
    Ok I have an uncut 1970 LS-6 motor with closed chamber square port heads. The heads have been CC'd at 108cc. They were 110 but milled a little. I want to keep a comp. ratio of about 10:1 (not much higher). I want forged full floating. I have searched summit and Flatlander and when I think that something looks good until I click on the details and it states (open chamber heads). I think I read somewhere you can use closed chamber pistons on open chamber heads but cannot use open chamber pistons on closed chamber heads. Correct me if I am wrong.
    The block will be cut .030 over and swinging a stock forged crank with eagle H-beam rods. Please give ideas and part numbers.
    Thanks.
    T.J.TJS call Doug Herbert Performance Parts and tell them everything you want in your set up and they will walk you thru it! their # is
    1-800-444-7373,,,,im running almost the same set up you have on the heads but at 104cc and a stroker crank with a 36 thousandths thick head gasket and right at 10-1, with flat top pistons and still able to run 87 octane!

  4. #4
    Boater Bill
    Check out SRP. They make closed chamber BBC pistons. Looks like 141635 is something that might work for you.
    Im using 143593's in my 489 with closed ch heads.

  5. #5
    396_WAYS_TO_SPIT
    Ok I have an uncut 1970 LS-6 motor with closed chamber square port heads. The heads have been CC'd at 108cc. They were 110 but milled a little. I want to keep a comp. ratio of about 10:1 (not much higher). I want forged full floating. I have searched summit and Flatlander and when I think that something looks good until I click on the details and it states (open chamber heads). I think I read somewhere you can use closed chamber pistons on open chamber heads but cannot use open chamber pistons on closed chamber heads. Correct me if I am wrong.
    The block will be cut .030 over and swinging a stock forged crank with eagle H-beam rods. Please give ideas and part numbers.
    Thanks.
    T.J.
    How far does your piston sit in the bore??? THat is going to play a role in the compression as well. Dont forget dome volume(cc's).

  6. #6
    mrgoslow
    you'll be happier with those heads if you find a machine shop to unshroud those valves but theres a chance of hitting water. as for pistons i used a set of keith black hypereutectic .133 dome pistons on a fully closed head before and after unshrouding with no problems. been in the hole since 99 no problems!

  7. #7
    TJS
    you'll be happier with those heads if you find a machine shop to unshroud those valves but theres a chance of hitting water. as for pistons i used a set of keith black hypereutectic .133 dome pistons on a fully closed head before and after unshrouding with no problems. been in the hole since 99 no problems!
    No Hypers. I have had probs with KB Hypers in a buddys boat. Broke the piston at the pin in about an hour of running. I think I am going with the SRP's. The heads are at the machine shop now. I will talk to them about unshrouding.
    Thanks.
    T.J.

Similar Threads

  1. Need BBC Closed Chamber Heads
    By Clearlake Kid in forum Parts 4 Sale
    Replies: 2
    Last Post: 11-02-2007, 07:49 PM
  2. '93 454 engine with '68 closed chamber heads
    By budnikjet in forum Gear Heads
    Replies: 11
    Last Post: 03-11-2007, 08:03 AM
  3. Closed Chamber VS Open Chamber Heads
    By PC Rat in forum Gear Heads
    Replies: 7
    Last Post: 03-27-2005, 03:38 PM
  4. Piston Chamber Cleaning and Piston Cleanup ?
    By baddassbaron in forum Gear Heads
    Replies: 5
    Last Post: 05-10-2004, 03:44 AM
  5. Closed chamber heads....
    By Bryan Rose in forum Gear Heads
    Replies: 9
    Last Post: 11-30-2003, 04:03 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •