cometic headgasket for LQ4 6.0L engine, HELP with decision!!! (Page 1/2) m0sh_man AUG 03, 11:12 AM i putting a 6.0L LQ4 engine into my 05 silverado 1/2 ton, im replacing my 270,000 mile LM7 5.3L motor, while its out im replacing the cam, lifters, valve springs, torque converter, and several other small items, anyway im planning on using the cometic headgaskets so i can run a thin gasket to boost compression, anyway i found these on ebay, but im not really sure if they will work or not, it says ls1, sl2 and ls6, well wheni look up the real specs on the part #, it looks like a 3.91" bore on the gasket, yet the 6.0L is a 4.0" bore http://www.ebay.com/itm/Com...96511#ht_1409wt_1397 hoping someone has some insight on if this will work or not. blander66 AUG 03, 03:58 PM nope you will need the ones with the bigger bore, I ran into this same issue when building a 5.3, I got the headgaskets then had the block bored .125" over and ended up having to get different head gaskets m0sh_man AUG 04, 01:12 AM yeah the guys at texas speed told me the same thing, i ordered the 4.035" bore cometic gaskets with .040 thickness, my donor motor is a 02 LQ4 6.0L its going into a 2005 silverado ext. cab longbed, 4x4, i ordered a TSP 220R cam, i got it with 111 LSA also ordered new valve springs, lifters, headbolts, headgaskets, intake gaskets, valve cover gaskets, oil pan gaskets, oil pump o-ring, torque converter, longtube headers, K&N full airbox kit. stock power from the LQ4 is 325HP and 360ft/lbs ill be happy if i can get 350HP and 380ft/lbs at the wheels, i think thats optimistic enough, my 5.3L has 270,000 miles on it, and the lower end of the LQ4 has 142,000 on it, if i get 60,000 miles outta the lq4 with these mods then ill be happy, it will take me about 10-12 years to put 60,000 miles on the truck. matthew CowsPatoot AUG 05, 03:53 AM I am very interested in how this works out for you. Have a build thread for this somewhere? I have a 2001 Z71 with 210k miles on the 5.3, and am planning on doing something similar when the engine goes (mildly built LQ4)...fortunately, it acts as though its going to be a while. m0sh_man AUG 05, 07:29 PM quote Originally posted by CowsPatoot: I am very interested in how this works out for you. Have a build thread for this somewhere? I have a 2001 Z71 with 210k miles on the 5.3, and am planning on doing something similar when the engine goes (mildly built LQ4)...fortunately, it acts as though its going to be a while. my 5.3L still runs great, great power, but with 3.42 gears i feel im lacking some low end power, plus my oil pump o-ring is leaking, and you have to pull the motor out to repair that, so i figured what the hell, id swap in a LQ4, i purchased a 02 2500HD at a salvage auction and parted out everything but the motor, so far ive made my entire $2200 investment back, plus an extra $300, i still have the front and rear differentials from the 2500HD that i can sell. *IF* i could fit the 8 lug rear end under my truck and keep my 6 lug axles, it would be under my pickup (4:10 gears with locker) when i start the build ill take notes, and maybe post the whole ordeal on here. right now i gotta figure out how much a bedside is going to cost for the drivers side, i let a friend borrow it last night, and he called me today and said im going to be mad at him, he put a "ding" on my truck..... when i got outside, it was a 24x36 dent down the side of the bed where he cut a turn too sharp and scraped the bedside down a pole, luckily once it got the edge of my tire it pushed the truck away from the pole and didnt do anymore damage down the side. Im sure he'll take care of it, but, i now have another thing i have to fix (guess ill replace my rocker panels at the same time, they are starting to get little rust spots on them) matthew blander66 AUG 06, 10:06 AM quote Originally posted by m0sh_man: *IF* i could fit the 8 lug rear end under my truck and keep my 6 lug axles, it would be under my pickup (4:10 gears with locker) If you have the 10.5 AAM axle I have seen people modify the hubs to be able to run 6 lug rims on them m0sh_man AUG 06, 09:01 PM quote Originally posted by blander66: If you have the 10.5 AAM axle I have seen people modify the hubs to be able to run 6 lug rims on them pretty sure i have the big 11.5" rear, its a 14 bolt i know that, its from a HD model, i think the 10.5 is from a 2500 (non-HD) matthew blander66 AUG 07, 11:00 AM quote Originally posted by m0sh_man: pretty sure i have the big 11.5" rear, its a 14 bolt i know that, its from a HD model, i think the 10.5 is from a 2500 (non-HD) matthew Usually only the duramaxs got the 11.5, but either way it does not matter, they share the same hubs, lockers are just cheaper for the 10.5. The only reason they devloped the 11.5 is the 10.5 was seeing ring gear teeth fatigue failures behind the dmax's. I used to work as a engineer at the plant where the 11.5 was produced. The guy I know that converted his to 6 lug used a older version so the hubs were already a little smaller in diameter, but he had the hub turned down a bit to allow the wheel to fit over it, then the wheel mounting flange was turned down and re drilled for the smaller pattern. Also what do you have left from the truck? I have a 05 dmax and may be intrested in some parts m0sh_man AUG 07, 10:06 PM not a whole lot, ill double check to see if it really is the 11.5, i do still have the entire rear drop out, the transfer case (option NP1) the front differential, and some other odds and ends, i also have the frame, its a 02 2500HD ext. cab short bed. matthew blander66 AUG 10, 09:35 AM quote Originally posted by m0sh_man: not a whole lot, ill double check to see if it really is the 11.5, i do still have the entire rear drop out, the transfer case (option NP1) the front differential, and some other odds and ends, i also have the frame, its a 02 2500HD ext. cab short bed. matthew I would mostly be looking for a front bumper if its a GMC and some interior parts Thanks