What are the best stock heads to have for the LS1
07-10-2010, 02:18 PM
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What are the best stock heads to have for the LS1 I have a truck motor, LS1 Iron block, and was wondering what heads are better, truck, corvette, camaro, firebird, gto, I was cruising craigslist when I got the idea of asking this. as you can tell from my username, I'm putting an LS1 w/ 700R4 & 8.8 posi rear end in a 1967 Mustang Coupe, and it's going to be the only one that I know of in existence with that drivetrain combination 
07-10-2010, 02:35 PM
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If you are looking for stock heads (not aftermarket), the Vette LS6 or GTO/Vette LS2 heads are probably the ones to get. They are all 243 casting heads (true LS6 heads have lighter valves). Edit: sometimes, the Vette LS2 heads are 799 casting).
07-11-2010, 03:27 AM
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I have a truck motor, LS1 Iron block, and was wondering what heads are better, truck, corvette, camaro, firebird, gto, I was cruising craigslist when I got the idea of asking this. as you can tell from my username, I'm putting an LS1 w/ 700R4 & 8.8 posi rear end in a 1967 Mustang Coupe, and it's going to be the only one that I know of in existence with that drivetrain combination
07-11-2010, 04:17 AM
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Like the other posted, the 243/799 LS6/LS2 heads are the way to go. If you can snag a set off of an 02+ Z06 with the lightweight valves thats a plus as well.
07-11-2010, 12:18 PM
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I have a truck motor, LS1 Iron block, and was wondering what heads are better, truck, corvette, camaro, firebird, gto, I was cruising craigslist when I got the idea of asking this. as you can tell from my username, I'm putting an LS1 w/ 700R4 & 8.8 posi rear end in a 1967 Mustang Coupe, and it's going to be the only one that I know of in existence with that drivetrain combination
there was however, a 1999/2000 model with a 5.7L Vortec (LTx like in the 95-98 trucks)
07-11-2010, 11:09 PM
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You do know LS2 and LS6 heads are identical, and will both fit the LS1 3.9 inch bore as well as the LS2 4 inch bore? Don't misinform the guy!
Like the other posted, the 243/799 LS6/LS2 heads are the way to go. If you can snag a set off of an 02+ Z06 with the lightweight valves thats a plus as well.
Like the other posted, the 243/799 LS6/LS2 heads are the way to go. If you can snag a set off of an 02+ Z06 with the lightweight valves thats a plus as well.
LS1, LS6 and LS2 heads will fit an LS1 and LS6 block
LS1, LS6, LS2, L92 and LS3 heads will fit an LS2, L92 and LS3 block.
LS1 / LS6 blocks are 3.89" bore
LS2 blocks are 4.00" bore
L92 / LS3 blocks are 4.065" bore
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07-12-2010, 02:52 AM
#8
Sorry guys I stands corrected, According to the GMPP catalog:
LS1, LS6 and LS2 heads will fit an LS1 and LS6 block
LS1, LS6, LS2, L92 and LS3 heads will fit an LS2, L92 and LS3 block.
LS1 / LS6 blocks are 3.89" bore
LS2 blocks are 4.00" bore
L92 / LS3 blocks are 4.065" bore
LS1, LS6 and LS2 heads will fit an LS1 and LS6 block
LS1, LS6, LS2, L92 and LS3 heads will fit an LS2, L92 and LS3 block.
LS1 / LS6 blocks are 3.89" bore
LS2 blocks are 4.00" bore
L92 / LS3 blocks are 4.065" bore
Yep thats good info. 
07-12-2010, 04:21 PM
#11
96 up truck engines were all badged as vortecs, the 5.7 heads made the vortec name popular. I think some 4.3's got the badge first, not too sure, and the 98 2.2 s-10 motor got the vortec name as well.
Anyways, back to topic. Lets try and figure out which engine you got.
1) heads should give a really good idea of which engine you got, and what diplacement it is. based on production numbers though, its probably a 5.3.
the head casting number is a small casting pad (external) on the outer perimeter of the valve cover surface, in the lower right hand side (facing the engine from either side) Number is three raised digits.
862/706 heads will be a 4.8 or 5.3. A 5.3 will have dished pistons with these heads, a 4.8 will have flat-tops - a good use of a flashlight might make this visible.
317 heads will be 6.0, either lq4 or lq9. lq4's get dished, lq9 get flat-tops
243/799 heads - 2007 up 5.3 with flat-tops, not sure of whether 4.8's get these heads.
Theres still the 07 up 6.0's, but I don't know what the numbers are for that, someone else might chime in for that. Pretty sure you didn't get that though.
Anyways, back to topic. Lets try and figure out which engine you got.
1) heads should give a really good idea of which engine you got, and what diplacement it is. based on production numbers though, its probably a 5.3.
the head casting number is a small casting pad (external) on the outer perimeter of the valve cover surface, in the lower right hand side (facing the engine from either side) Number is three raised digits.
862/706 heads will be a 4.8 or 5.3. A 5.3 will have dished pistons with these heads, a 4.8 will have flat-tops - a good use of a flashlight might make this visible.
317 heads will be 6.0, either lq4 or lq9. lq4's get dished, lq9 get flat-tops
243/799 heads - 2007 up 5.3 with flat-tops, not sure of whether 4.8's get these heads.
Theres still the 07 up 6.0's, but I don't know what the numbers are for that, someone else might chime in for that. Pretty sure you didn't get that though.
02-13-2014, 11:46 AM
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Heads for "LS1 iron block" I'm not sure if GM put an iron LS 5.7 in early trucks, but I have a early model 5.3 in the machine shop, and they are telling me, later model 5.3's have flat top pistons. I "THINK" 2006 on up.
Things at GM have changed from their old way of doing business. They now add new parts, and change engine configurations, at the speed of marketing.
Things at GM have changed from their old way of doing business. They now add new parts, and change engine configurations, at the speed of marketing.
11-05-2015, 09:56 AM
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It doesn't matter if the OP has a genIII iron block truck engine, 4.8 or 5.3, and is simply referring to it as an ls1 to denote it is a genIII, not IV. It doesn't matter if he has an iron block of either generation bored to 3.9" for a 5.7, and that's why he called it an ls1.
Ls6 243's are still the best factory heads for the 3.78 and 3.9" bore blocks, period. Once you get into the 4" bore you can use ls3 heads, but this discussion isn't about that.
Ls6 243's are still the best factory heads for the 3.78 and 3.9" bore blocks, period. Once you get into the 4" bore you can use ls3 heads, but this discussion isn't about that.
11-05-2015, 10:13 AM
#18
It doesn't matter if the OP has a genIII iron block truck engine, 4.8 or 5.3, and is simply referring to it as an ls1 to denote it is a genIII, not IV. It doesn't matter if he has an iron block of either generation bored to 3.9" for a 5.7, and that's why he called it an ls1.
Ls6 243's are still the best factory heads for the 3.78 and 3.9" bore blocks, period. Once you get into the 4" bore you can use ls3 heads, but this discussion isn't about that.
Ls6 243's are still the best factory heads for the 3.78 and 3.9" bore blocks, period. Once you get into the 4" bore you can use ls3 heads, but this discussion isn't about that.
11-05-2015, 10:20 AM
#19
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Yeah, I didn't notice that until after I replied because I'm an idiot. Just another gravedigger trying to jack up their post count for the classifieds...
