ChevelleSS Posted June 1, 2003 Report Share Posted June 1, 2003 What is the diffence in the LQ4 and LQ9 engines? I have heard that the LQ9 (H.O.) has a little more compression but is that the only difference in the two to gain the additional 45 hp? Quote Link to comment Share on other sites More sharing options...
Bear Posted June 1, 2003 Report Share Posted June 1, 2003 The LQ4 & LQ9 are very closely linked, the LQ9 has LS6 based heads with the same combustion chamber volume as the LQ4. The extra compression comes by different pistons. They use identical cam specs. as does even the base motor in the Vett. So we can see the extra hp came from more compression, slightly different heads "same port vollumes" & different programing in the computer. Bear: 01"Pewter"C3 Quote Link to comment Share on other sites More sharing options...
BigTex Posted June 1, 2003 Report Share Posted June 1, 2003 Not quite correct. Hypereutectic flat top pistons on the LQ9, cast dished pistons on the LQ4. Same heads on both motors. If you have an LQ9, look at the casting number - 317. Same as on the LQ4. The stated HP numbers from GM are sort of a game anyway. Look at how they rate the LQ4 on the other platforms. They rate different HP on the Denali vs the trucks, but its the same physical motor. Same thing they did with the Z28 and Camaro SS. Same physical motor, one has a differnt air intake - instant 20 HP ratings. Quote Link to comment Share on other sites More sharing options...
Bear Posted June 1, 2003 Report Share Posted June 1, 2003 I'm not saying GM is perfect in any way as you possibly may have the wrong casting number on them but the LQ9 head part # is 12572035, casting identifiable as 035, the LQ4 head is part # 12562317 which you know is identifiable as 317. I would say the only way to know for sure is to find the whole part # which is located under the valve cover between the push rod holes. By the way I do agree with you about differece in pistons as said the two heads carry the same combustion chamber vollume. Bear: 01:Pewter"C3 Quote Link to comment Share on other sites More sharing options...
BigTex Posted June 2, 2003 Report Share Posted June 2, 2003 Bear, I hope you aren't getting your info from an article in the March (or Feb) issue of GM High Tech Performance magazine or the book "Chevy LS1/LS6 Performance", both by the same author- Chris Endres. I have some concerns about that source. I have yet to see an 035 head. I've looked on SSs and Escalades and have not seen one. My LQ9 has 317 heads. Does anyone here have 035 heads on their SS? Quote Link to comment Share on other sites More sharing options...
Krambo Posted June 3, 2003 Report Share Posted June 3, 2003 Does anyone here have 035 heads on their SS? 317 here Quote Link to comment Share on other sites More sharing options...
BenKey Posted June 9, 2003 Report Share Posted June 9, 2003 Also 317. Quote Link to comment Share on other sites More sharing options...
mcwarren Posted June 10, 2003 Report Share Posted June 10, 2003 317 here also. Quote Link to comment Share on other sites More sharing options...
Tex Posted May 11, 2010 Report Share Posted May 11, 2010 317 here to Quote Link to comment Share on other sites More sharing options...
2bfast Posted May 11, 2010 Report Share Posted May 11, 2010 317 here to Notice the date on this thread?? lol Quote Link to comment Share on other sites More sharing options...
kcsilveradoss Posted May 11, 2010 Report Share Posted May 11, 2010 My thread shovel has a 317 cast into it Quote Link to comment Share on other sites More sharing options...
Bear Posted May 12, 2010 Report Share Posted May 12, 2010 Yep, proven time and time again.........LOL Quote Link to comment Share on other sites More sharing options...
dragpny Posted January 3, 2013 Report Share Posted January 3, 2013 Not to beat a dead horse but is that the difference between a N code and U code. N code LQ9/345hp U code LQ4 300hp. I triing to pick up a LQ 9 for my LS mustang swap and want to get the right one. Found an 05 caddy LQ9. Thanks. Quote Link to comment Share on other sites More sharing options...
BLNAWAY Posted January 3, 2013 Report Share Posted January 3, 2013 (edited) Not to beat a dead horse but is that the difference between a N code and U code. N code LQ9/345hp U code LQ4 300hp. I triing to pick up a LQ 9 for my LS mustang swap and want to get the right one. Found an 05 caddy LQ9. Thanks. this thread is 3yrs old FYI ....but from what I read above the difference is the pistons..... but I no expert on this just glanced thru seems to have same head,cam just different piston Edited January 3, 2013 by BLNAWAY (see edit history) Quote Link to comment Share on other sites More sharing options...
canadianVRss Posted January 3, 2013 Report Share Posted January 3, 2013 connecting rods are beefier in the lq9 as well Quote Link to comment Share on other sites More sharing options...
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