View Full Version : Lq9 lq4

10-27-2009, 09:11 PM
when buying one of these engines say from a junkyard or such how do you know which one it is? also are these engines considered a ls(what) ? if they are. or are they just ls based?

10-29-2009, 09:52 PM
Best to know which vehicle carried which engine. The LQ9 would be found in Cadillacs, Silverado SS, Silverado/Sierra HO and Silverado/Sierra VortexMax. The LQ4 is a bit tricker but pretty safe in the 2500 and 3000 class pickups and anything in Denali.

I would recommed you type in LS or Vortec into Wikipedia and do some research. I would like to say that all of the "newer" GM engines are part of the LS family and share many components. The LS1,2, 3....and such, became infamous as performance engines but are the "car" version of the 8 cylinder while all the other 8 cylinders are truck versions and come in many configurations.

10-29-2009, 10:40 PM
An LQ9 is a "high output" LQ4. The compression is upped a little, and it's usually called a VortecMAX.

If you go 2007 and up, you'll get into L76's which have variable valve timing, and active fuel management and all that fun stuff...

10-30-2009, 06:35 PM
thank you both for the info.

so other then compression they are the same? how do they the up compression?different heads or different pistons? or both? im going to swap heads on the engine so if thats how they did it i guess the easier to come by lq4 would be the rote to go? i also want to run a procharger or to sell the D1SC i have and go turbo but that wont be untill after i get it in the car and running. its also going to be a carbed setup.

10-30-2009, 09:24 PM
I would guess pistons as I would bet the heads are the same. I could be totally wrong about that though....The LQ4 should be more abundant and less expensive so good choice there. Cams on all of these truck engines are pretty mild so minus intake (you're going carb so this wouldn't apply) it would be your best, and easiest, bang for the buck.

10-30-2009, 09:26 PM
if your gonna use the block and crank to build your own motor just get the LQ4. its far more common and cheaper.

10-30-2009, 10:25 PM
lq4 has dished pistons and lq9 has flat tops i would buy an lq4 if your gonna replace any internal and an lq9 if you were gonna leave it alone

10-31-2009, 09:10 AM
SmoknZ is right :D

10-31-2009, 09:24 AM
So they have the same internals any better years for stronger bottom ends. Doing 6.0 swap in 1996 mustang and just want the strongest bottom end tell ready to upgrade to stroker later on.

10-31-2009, 10:59 AM
My standard disclaimer applies here "I could be totally wrong" but the bottom ends are identical and I don't believe there has be any bad year compared with any other years. I would concentrate on finding the lowest milage engine and go from there.


10-31-2009, 12:00 PM
I think some of the newer engines have better connecting rods then earlier years.....

10-31-2009, 01:32 PM
ok thanks guys lq4 it is, im looking to get an engine to drop in to a 86 mustang. i want to get all the parts and do the entire swap in the spring(if not sooner). how strong are the stock parts? crank rods pistons? ive heard i should change out the rod bolts. what about main bolts?

10-31-2009, 02:23 PM
i would use arp bolts through out so your gonna boost this motor? spray it? leave it N/A?

btw not many people change the main bolts when they have a 6.0L project the 6.0 is a budget motor IMO i would get an LS2 if the funds were not a problem

10-31-2009, 02:29 PM
the funds are a problem haha this is a tight budget build. but with out skimping. i would like to make it a 10.0 car. im thinking about boosting it i had a D1SC on my truck(dakota)and loved it and i still have the d1sc and have to find out if it will work on a 6.0 with just a reclock.

10-31-2009, 02:39 PM
I was planning on upgrading rod bolts. Just going to be ported heads, fast 92mm ported intake and cam. Have performa built 4l60e and 4600 stall level 2, full lengh kook headers 8.8 with 3.73s maybe 100 shot later on. Does any one no someone that can spec out a cam to run with my combination.

10-31-2009, 02:54 PM
ported #317's? you might want to get them milled them they are 72cc stock i belive

10-31-2009, 06:51 PM
when buying one of these engines say from a junkyard or such how do you know which one it is? also are these engines considered a ls(what) ? if they are. or are they just ls based?

ls is the same as lq, they are the same box and size

lq9 if you want the new setup with flat top pistons, rods are different
lq4 less compression.

Depends on the size of engine


11-01-2009, 12:19 AM
My heads are patriot performance with 2.05 intake valves and has 64cc chambers 227c runners. Any one have ideas for cam to run drive ability not as important as overall performance on the strip. Will b LQ4 short block

11-02-2009, 01:13 PM
bump bump

11-08-2009, 09:31 PM
another question how can you tell a lq9 from a lq4 out of car ? casting numbers?

12-16-2009, 06:46 PM
LQ9=Flat top pistons
LQ4=Dish pistons

12-16-2009, 07:02 PM
LQ9=Flat top pistons
LQ4=Dish pistons

what he said

12-16-2009, 07:22 PM
i justed pick up a 6.0l the price was right so it ended up not mattering about it being 4 or 9 im going to put new rods and pistons in it.

12-18-2009, 12:37 PM
Very cool.
I'm working on a 6.0 myself. Also a budget build.
Please post any progress (in appropriate forum of course ;-)

12-18-2009, 01:28 PM
I picked up some LS2 rods/pistons for mine for $120, Ls1 crank(24t reluc.) for $50, LS6 oil pump for $40, and HD timing chain set(including sprockets) for $62. I just need to get Rod/Main Clevite bearings, Rod/Main ARP bolts, Lifters, water pump, and Cam and my shortblock will be done. SO I fuigure about another $500-700 depending on the cam I choose which will be huge.

12-18-2009, 06:03 PM
ok no problem.

what lifters are you going to be using?

12-18-2009, 06:48 PM
Not sure yet ! I people using LS7 lifters all the time ! I might go with those !