Generation III Internal Engine - which head gaskets?
04-30-2012, 04:35 PM
Hey guys cant aeem to get a good answer locally. What i have is a lq4 block bored.040 . Which head gaskets do i need to run? I was told stock but noticed the bore diameter on a stock gasket for a 4" bore has a diameter of 4.040 . Giving .040 clearance around piston bore. Stock gaskets ok? Im running flat tops which protrude deck height barely . And running 243's ported and milled .010 . Cam is a 224/230 .609/.604 on a 112 lsa.
thanks in advance guys
04-30-2012, 04:42 PM
cometic probably has something that will work for you
04-30-2012, 04:49 PM
Stock L92/Ls3 gasket would work fine
04-30-2012, 08:45 PM
Thought the ls3 / l92 heads were different or is the just on the intake ports.?
04-30-2012, 08:57 PM
The GM MLS will fit LS2/L92/LS3/L99 engines.
04-30-2012, 10:09 PM
Thanks guys this was the last thing i needed to order to finish motor up getting heads back this week n shell be ready to go :)u finally after 2 yrs being off the road!
05-01-2012, 10:59 AM
Your gaskets should be at least .030 in. bigger than bore.
05-03-2012, 05:37 AM
Omly thing im finding is stock 4.100 or a cometic 4.060 anyone have a part numberor manufacturer of a 4.070 or a 4.080 gasket?
06-01-2012, 06:13 AM
Only thing i could find was cometic 4.060 with athe thickness of .051 an installed those bore size is 4.040 . Any issues im looming at? Everyone i talked to lovally n on the phone said no problem . Any issues that stand out problems this could cause? Running stock head bolts. Heads r milled .010
06-01-2012, 07:41 AM
Dont see why you didnt just tun the stock .051 thou ls3 gaskets.... They are a 4.085 bore
06-01-2012, 10:53 AM
Was told to go with cometic for compression reasons .everyone said never had an issue with blowout with cometic. Gm mls gaskets were the death of the last build hydro locked #6himself cylinder n all hell broke loose from there. Only thing reuseable were the covers n the oil pan :(
06-01-2012, 10:54 AM
Plus got the cometics for dealer price so $120 for both .
too late now But i measure how far each piston comes above the deck surface, lets say for example my 383 its at .012 above the deck, most ls engines are above the deck but you need to know exactly how much if you are trying to maximise your combo
i run a minimum of .032 quench aka the clearance between the top of piston to the cylinder head deck, a good range for steel rods is .035-.040 for 11-1 compression ls engines, That Quench is important for running hi compression on pump gas
I also run a large bore 4.125 gasket because it matches the chambers in my heads, you DO NOT want a head gasket that is smaller that your chamber! Good way to kill flow, power and cause other issues, Bore size of the engine plays a very little role in my head gasket choosing, BTW Flat Out makes Very Nice MLS gaskets as well as cometic
06-03-2012, 07:54 AM
Pistons cleared the deck heighth .01 . The cometic gaskets were .051 n i have a ptv of .157 and .185 . Called cometics tech support sn they said the 4.060 gaskets were an excellent choice for my setup and would be fine with no problems. Also talked to another vendor/engine builder on this site that said no problemo run'm .