LS2 with LS3 heads valve clearence question
03-20-2013, 07:37 PM
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LS2 with LS3 heads valve clearence question hey, My name is chris and im building a drift car with an LS2 6.0L with LS3 heads, and i have a few Questions.....
1. I hear that milling the heads .030" will get me back to stock compression ratio. is this true in a "ball park sence" and could i just get a thinner head gasket to achieve this?
2. From what i can find the stock head gasket is about .060" thick so in theory could i run a cometic MLS head gasket for the LS2 with a bore of 4.030" and thickness of .030" to get me back close to stock compression ratio?
3. Im going to be running a "LSR™ Rectangular Port, 281LRR HR13" cam with a intake lift of .617" and exhaust lift of .634" with running high lift springs in the LS3 head and stock rocker arms with a 1.7 rocker arm ratio would i have any clearence isues with the stock LS2 flat to pistons and the head gasket im going to be running?
4. Im planning on running my stock LS2 lifters/followers. will they hold up to the higher lift of the cam?
5. im also going to run some comp cam push rods. Can i run stock lenght or do they have to be shorter.
keep in mind this is a set im doing just for one season and plan on building the engine for boost next season. i just am trying to get as close to 500hp as i can with this na set up. also will be jumping up to roller rockers and better internals for next season. i hope some one out there has done this before and can go over my numbers and let me know if im in any risk of clearence issues before i asyemble these heads to the block. thank you four your time in reading this post!
Chris J
1. I hear that milling the heads .030" will get me back to stock compression ratio. is this true in a "ball park sence" and could i just get a thinner head gasket to achieve this?
2. From what i can find the stock head gasket is about .060" thick so in theory could i run a cometic MLS head gasket for the LS2 with a bore of 4.030" and thickness of .030" to get me back close to stock compression ratio?
3. Im going to be running a "LSR™ Rectangular Port, 281LRR HR13" cam with a intake lift of .617" and exhaust lift of .634" with running high lift springs in the LS3 head and stock rocker arms with a 1.7 rocker arm ratio would i have any clearence isues with the stock LS2 flat to pistons and the head gasket im going to be running?
4. Im planning on running my stock LS2 lifters/followers. will they hold up to the higher lift of the cam?
5. im also going to run some comp cam push rods. Can i run stock lenght or do they have to be shorter.
keep in mind this is a set im doing just for one season and plan on building the engine for boost next season. i just am trying to get as close to 500hp as i can with this na set up. also will be jumping up to roller rockers and better internals for next season. i hope some one out there has done this before and can go over my numbers and let me know if im in any risk of clearence issues before i asyemble these heads to the block. thank you four your time in reading this post!
Chris J
03-21-2013, 06:34 AM
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1. just about.
2. stock gasket is .051, not .060.
3. you can expect to have ptv clearance issues with thinner gaskets or milled heads.
4. stock ls2 lifters will hold up. however, i would consider replacing with ls7s if the ls2s have higher mileage.
5. depends on use of which gaskets and milling. last thing you would want to choose.
NOTE: you may want to consider flycutting on the pistons to increase clearance for milling and using thinner gaskets to raise compression.
however, i have an lq9 (iron ls2) with ls3 heads. i milled my heads .015 to help raise compression but only to minimum as milling affects airflow. i also used cometic .040 gaskets to help raise compression plus they suppose to help with quench and preventing detonation. this brought me to bought stock ls2 compression of 10.9:1. my cam of choice is a 232-238, 598-600, 113+4 and it cleared without flycutting.
a very popular proven cam for this type of combo (ls2 with ls3 heads) is the fti tigershark with 232-236, 600-600, 113. i found out a lil late or id be running the fti tigershark. since very similar to mine, i would think it would clear also without flycutting.
good luck with your project. hope this helps.
2. stock gasket is .051, not .060.
3. you can expect to have ptv clearance issues with thinner gaskets or milled heads.
4. stock ls2 lifters will hold up. however, i would consider replacing with ls7s if the ls2s have higher mileage.
5. depends on use of which gaskets and milling. last thing you would want to choose.
NOTE: you may want to consider flycutting on the pistons to increase clearance for milling and using thinner gaskets to raise compression.
however, i have an lq9 (iron ls2) with ls3 heads. i milled my heads .015 to help raise compression but only to minimum as milling affects airflow. i also used cometic .040 gaskets to help raise compression plus they suppose to help with quench and preventing detonation. this brought me to bought stock ls2 compression of 10.9:1. my cam of choice is a 232-238, 598-600, 113+4 and it cleared without flycutting.
a very popular proven cam for this type of combo (ls2 with ls3 heads) is the fti tigershark with 232-236, 600-600, 113. i found out a lil late or id be running the fti tigershark. since very similar to mine, i would think it would clear also without flycutting.
good luck with your project. hope this helps.
03-27-2013, 02:27 PM
#6
however, i have an lq9 (iron ls2) with ls3 heads. i milled my heads .015 to help raise compression but only to minimum as milling affects airflow. i also used cometic .040 gaskets to help raise compression plus they suppose to help with quench and preventing detonation. this brought me to bought stock ls2 compression of 10.9:1. my cam of choice is a 232-238, 598-600, 113+4 and it cleared without flycutting.
a very popular proven cam for this type of combo (ls2 with ls3 heads) is the fti tigershark with 232-236, 600-600, 113. i found out a lil late or id be running the fti tigershark. since very similar to mine, i would think it would clear also without flycutting.
good luck with your project. hope this helps.
a very popular proven cam for this type of combo (ls2 with ls3 heads) is the fti tigershark with 232-236, 600-600, 113. i found out a lil late or id be running the fti tigershark. since very similar to mine, i would think it would clear also without flycutting.
good luck with your project. hope this helps.
