l92 heads on lq9 6.0

[skeet]

i been reading and understanding this artical from hotrod mag.

How to Add Horsepower to GM's 6.0L Ls-Series Small-Block - Hot Rod Magazine


but what i am getting is the stock lq9 bore is 4" (or is it smaller) which is marginal for the l92 heads. i guess my questions would be how marginal? i do understand the l76 intake would need to be used or the fast90 ( wonder if theres any others) and some bracketery from a camero, none of this is not obtainable. can be done rather cheaply, anyway gonna read and research more into this as it seems like a postive route to go in... if its as promising as it seems..


anyway just some thinking out load and any input is more than welcome!!!!

[PurpleMinivan]

L92 heads would fit on your LQ9. You can use the L92 truck intake, the L76 car intake and a wieand and fast 92 will be out soon for the heads. with the heads decked you could obtain you stock compression back. I would suggest a stage 1 P and P on the heads with stock short block. You would not have to change any accessories with the L92 truck intake, or you can go to gto accessories (about $500) if you use the car intakes.

[skeet]

L92 heads would fit on your LQ9. You can use the L92 truck intake, the L76 car intake and a wieand and fast 92 will be out soon for the heads. with the heads decked you could obtain you stock compression back. I would suggest a stage 1 P and P on the heads with stock short block. You would not have to change any accessories with the L92 truck intake, or you can go to gto accessories (about $500) if you use the car intakes.

thanks for the info bro, much appreciated, my concern was making sure i didnt have any valve shrouding..so basically understanding the artical and your post, this wouldnt be a bad setup? yes i was planning on having a port and polish done. i also noticed theyre really not that expensive, my thoughts were going this route or the 243 heads from patriot.. jsut trying to figure out whats the best bang for the buck!!!!

p.s. thanks again, gonna do somemore research

[PurpleMinivan]

Just my opinion, unless you can bump the CR up to around 11 to 1,or add FI, or spray, they might be a little sluggish on the bottom. They are very nice heads for $350; for bare castings. Any head that flows 320int./230exh. out of the box is pretty damn good. The exhaust flow needs a little help, thats where the P/P would come in. I would port the exhaust side and just clean up the intake side if I were putting them in a LQ9 or a LS2. Ported 243's aren't bad pieces either for what you have. If you go with L92's I would suggest another cam than what you have, with that said a cam is just adding more $$$ to the best bang for the buck for you.

[skeet]

Just my opinion, unless you can bump the CR up to around 11 to 1,or add FI, or spray, they might be a little sluggish on the bottom. They are very nice heads for $350; for bare castings. Any head that flows 320int./230exh. out of the box is pretty damn good. The exhaust flow needs a little help, thats where the P/P would come in. I would port the exhaust side and just clean up the intake side if I were putting them in a LQ9 or a LS2. Ported 243's aren't bad pieces either for what you have. If you go with L92's I would suggest another cam than what you have, with that said a cam is just adding more $$$ to the best bang for the buck for you.

thanks, yes i was gonna go with another cam also, just hadnt decided on what size was thinking somewere in the 230+ 600 lift max range, any thoughts on this one?

[freemaSSon]

thanks, yes i was gonna go with another cam also, just hadnt decided on what size was thinking somewere in the 230+ 600 lift max range, any thoughts on this one?

we had my L92's decked to 62cc chambers and ran a LPE GT-11 cam on my LS2 that went 7.68 @ 89.11 in the 1/8th.....

the cam is 215/231 .631"/.644" with 1.7 ratio rockers an has a 118 LSA....we ran shorter push rod and no issues.....it was a MONSTER on the street and ran rediculously fast at the track......

just some input from been there done that.....i have gone to the stroker now and kept the L92 top end.....just badass.....

if i had it to do all over again i woul use these cam specs......

225/230 590/610 with 110 ICL 114 LSA with 4 degree cam advance on the COMP LSK Lobe....the 118 LSA was just too flat off the line for me i geared my truck down to get the best out of the setup which was probably the wrong thing to do.....a different cam would have been cheaper and worked better......



EDIT: where ever you land on the cam specs the duration over lap needs to be minimized on these heads and the lift split maintained.....this will increase cylinder pressures on the bottom to increase torque and the top end will alwyas flow with these heads do to the rrunner size

[skeet]

we had my L92's decked to 62cc chambers and ran a LPE GT-11 cam on my LS2 that went 7.68 @ 89.11 in the 1/8th.....

the cam is 215/231 .631"/.644" with 1.7 ratio rockers an has a 118 LSA....we ran shorter push rod and no issues.....it was a MONSTER on the street and ran rediculously fast at the track......

just some input from been there done that.....i have gone to the stroker now and kept the L92 top end.....just badass.....

if i had it to do all over again i woul use these cam specs......

225/230 590/610 with 110 ICL 114 LSA with 4 degree cam advance on the COMP LSK Lobe....the 118 LSA was just too flat off the line for me i geared my truck down to get the best out of the setup which was probably the wrong thing to do.....a different cam would have been cheaper and worked better......



EDIT: where ever you land on the cam specs the duration over lap needs to be minimized on these heads and the lift split maintained.....this will increase cylinder pressures on the bottom to increase torque and the top end will alwyas flow with these heads do to the rrunner size

thanks for the input FM, yeah also keeping into concideration that this is an ECSB, so the lsa12 would be feasiable?

[freemaSSon]

lower lift with TIGHTER LSA is your friend with the weight we all have and if you degree the cam it brings the torque on even earlier......

but it seems you are already leaning that way.......lower duration with larger lift increases the cylinder pressures and the DYNAMIC COMPRESSION is what gives you torque and with the L92's the heads flow TOO fast with that MONSTER intake runner, the trick is getting the head velocity to SLOW and build dynamic compression to build torque.....make sure you talk to as many cam ENGINEER/BUILDERS as possible to get the right cam combo for the L92 but not on the head but the head installed with the HUGE WEIGHT......

gm used a reverse split to SLOW DOWN head velocity and increase dynamic compression, which works but it is crap for anything after about 5500 rpm's......

my bride has an '08 escalade and it is just rediculous off idle but dies at 5000, just falls off COMPLETELY...the factory shift point are like 5500 rpms....and it is all centered around that reverse split....

[PurpleMinivan]

thanks, yes i was gonna go with another cam also, just hadnt decided on what size was thinking somewere in the 230+ 600 lift max range, any thoughts on this one?

224/232 .612/.595 112LSA with an XE lobe on the int./ XER lobe on the exh. would give you great TQ across the graph. Pat's suggestion would be great also. Either would work great for what you have and again they're just some numbers to play with. You can use the stock L92 rockers and ship them to Harland Sharp to get rebushed for ease of mind until the aftermarket steps it up on their rockers. Je$el and Yella Terra are the only ones making them for now and there's been 0 gains shown from either.

just some input from been there done that.....i have gone to the stroker now and kept the L92 top end

So...you kept the 62cc chambers which puts you at what CR? or did you use another set with larger chambers?

[freemaSSon]

So...you kept the 62cc chambers which puts you at what CR? or did you use another set with larger chambers?

NOPE no worky....the stock 72cc's would have been like 12 to 1

the new heads are LPE freaked and tweaked full CNC hollow stem intake on stock diameter with patriot gold extreme duals that have been CNC BOWLED to 74cc's and i am still above 11.6 to 1......

that 4.135 bore size is a killer....and that is flattop pistons with 10cc valve reliefs.....