ok now I know 2000+ LD9 had differnet pistons, head and no EGR, so what about the 99 year? since it was the bastard year where things changed, would LD9 with no EGR have same pistons as the 2000+ or the 96-99 style?one of my friends was asking me questions about it, and I said wasn't sure since I rebuilt my motor a while back so memory is a little rusty, I'm pretty sure the 99 without EGR was quite the same same the 2000+and the 99 year had 2 different pistons, and 2 different heads for that year of car, would I be wrong there?like I said been a while, and he thinks he can build a stronger motor then my P.O.S. lol


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

its been rumored that the 99 got both styles. i have yet to see it though.

i would love to know for sure so i can get the facts straight.



Familiar Taste of Poison.

same here, I wish I kept the old ones that I had lol


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

well i know for a fact i have seen a 99 with the skinny high impedance injectors as well as lacking the EGR so that is definitely myth busted.

i would just like to know if the internals were the same as 96-98 or 00-02.



Edited 1 time(s). Last edited Saturday, September 05, 2009 6:35 PM


Familiar Taste of Poison.

ya I have high impedence and no egr on my 99


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

apun further investigation it looks like the 99 head may be just the same as te 00-02 ones....

go read this thread and you can see a 99 exhaust port. i know this guy, he ported my 97 head. the head he has is for sure a 99. he bought the car brand new from the dealer and if he says it is a 99. it is. and also, recently he tried installing my speed pro stand alone ecu that had already been wired up to a 97 harness. he called and told me he needed an older injector harness because his would not work. so what does that tell me?? that its also got the skinny high impedance injectors. i will ask him when the build date of the car is as well as about his stock pistons.

basically.. if you look at the pic of the stock exhaust port picture, you can plainly see the slash protrusion in the port. no idea why gm did this but i know for a fact every 00-02 head shares this same protrusion.

here is a pic i took of a stock 2000 alero head i have...





Familiar Taste of Poison.

so basically if u have the 99 without egr then there would be no way to go to the 96 head seeing as how 96 had the egr,but we were debating on it cause he has same year as mine and same thing has no egr, he was wondering if putting on 96 head would help or not


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

amd BRad after readign that thread, looks like he had the 2000 head lol


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

My Alero is a 99 and I dont recall it having the protrusion on the exhaust ports.


GMR has got nothing on this

aj- doesnt matter anyway. ALL ld9 heads have the egr passage. you either need the gm egr block off plate or the 99.5-02 exhaust manifold gasket.



Familiar Taste of Poison.

well then putting on 96 head would benefit, but then still leaves aspect of the pistons, with non-egr is same as 2000+ or not


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

hell yea man. your compression will go up if you do have the flat tops.

if you can swing it go for the ss valves and possibly have the head decked for ever more.

and going back and reading pat's thread he did say it was a 2000 head so fawk idk LOL

i will ask him about it when i ask about the bottom end.



Familiar Taste of Poison.

ya I dont see it helping that much with compression, lets say using the 2000+ stock pistons, with 96 head, cant see more then .3-.5 increase in compression


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

maybe even less. but it's still more



Familiar Taste of Poison.

meh, you want more go 11:1 or 11.5 lol


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

an ideal n/a setup would be...

diamond 11:1 pistons .060 over bore
1mm os ss valves
96-99.5 head decked .020

talk about race gas needed.



Familiar Taste of Poison.

I have yet to see a 99 with EGR. We have a 99 block, but have never looked. Will check into this.



FU Tuning

Hey brad dont you have some diamond pistons?




"It's called reading! Top to bottom, left to right... a group of words together is called a sentence. Take Tylenol for any headaches... Midol for any cramps."

yup. and wisecos. and wisecos.





Familiar Taste of Poison.

Late year '99 with high impedance injectors, small starter, and no EGR. Combustion chambers 1-4 in order.









Look like flat tops to me. Couldn't tell you what the early year '99s look like, though.



- Interior FAQ -
J-Body of Michigan -

Listening, as always.


Misnblu.com
Newbie member since 1999
Thank you Dave and JBO!

be better to tell with no carbon but to me they look the part.

flat tops it is.

do you happen to have those out of the engine yet? because another dead give away is if the skirts have a teflon coating.



Familiar Taste of Poison.

so there we go 99.5 up have the flat top, so at least now I know mine must be domed a bit being 10:1, so 96 head, and 2000+ exhaust manifold should fix the egr aspect, so using 99.5+ block, with the 96 head that should net about .3-.5 compression, but that is stock and stock, so in reality get the head, port the exhaust side(maybe little polish), and shine up the valve ports and you should increase the compression a tiny bit more, ss valve would be nice but really not needed unless you plan on building it for turbo or mainly high-end torque, shaving the head could very much help.....but.........can also have downside if you plan to upgrade to my 10:1 or larger pistons a little less clearance, sure bigger bang but in long term aspect can damage. I think going to get 96 head and port, then tell him he cant run the 96 head lol


"As I lay rubber down the street, I pray for traction I can keep, but if I spin and begin to slide, please dear God protect my ride." -Amen

not the 99.5+ manifold... the 99.5+ gasket.

much cheaper and easier to find LOL

should do the egr block off plate to just to clean up the dumb hole on the front of the head to...



Familiar Taste of Poison.

and re-use the 99+ intake mani


Edited 1 time(s). Last edited Sunday, September 06, 2009 1:36 PM