So what's the difference in 5.3l vs ls6 heads?
09-22-2009, 11:00 AM
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So what's the difference in 5.3l vs ls6 heads? I've been searching and I know there are physical differences between these and a big price difference. I'm not asking "what is better" because I don't want any sort of subjective debating. I'm simply wondering what the differences in end results would be on a stock cube 346 that has a medium sized (234/238) cam.
Some have said the 5.3l will be higher compression and thus better low end torque and throttle response. Some say ls6 will make more power but at a higher rpm and at the cost of low rpm power.
Would I be leaving too much power on the table with the 5.3l? I like the thought of maintaining low end power but not if this will severely limit my choices later on.
I'm looking for a daily driver that sees 4 track trips a month (so it sees 20-40 runs a month in the season). With the torque converter install (3600rpm stall) my power has already been pushed up a bit in the rpms, I'd hate to be a dog down low (not that i street race a lot, but it's nice to have some power at low speeds).
On the same note, what's with the ls3 heads, l92, etc?
Hope this is not a really open ended question.
Some have said the 5.3l will be higher compression and thus better low end torque and throttle response. Some say ls6 will make more power but at a higher rpm and at the cost of low rpm power.
Would I be leaving too much power on the table with the 5.3l? I like the thought of maintaining low end power but not if this will severely limit my choices later on.
I'm looking for a daily driver that sees 4 track trips a month (so it sees 20-40 runs a month in the season). With the torque converter install (3600rpm stall) my power has already been pushed up a bit in the rpms, I'd hate to be a dog down low (not that i street race a lot, but it's nice to have some power at low speeds).
On the same note, what's with the ls3 heads, l92, etc?
Hope this is not a really open ended question.
09-22-2009, 11:23 AM
#2
5.3's have a smaller combustion chamber which will increase compression on your LS1.
LS6's flow more air, and have only a slightly smaller chamber than stock LS1 heads.
I would say it would be best to mill some LS6's to get the compression up but thats a pretty nasty camshaft and im not sure if it would have enough PtV clearance.
The ideal thing to do would be to measure the PtV clearance with that cam with the stock heads and see what kinda room you have. If you have enough where you can mill .030 or so off of a set of 243's than thats the route to go.
Hope this helps.
LS6's flow more air, and have only a slightly smaller chamber than stock LS1 heads.
I would say it would be best to mill some LS6's to get the compression up but thats a pretty nasty camshaft and im not sure if it would have enough PtV clearance.
The ideal thing to do would be to measure the PtV clearance with that cam with the stock heads and see what kinda room you have. If you have enough where you can mill .030 or so off of a set of 243's than thats the route to go.
Hope this helps.
09-22-2009, 12:16 PM
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TSP is who I was looking at.
Also, this is a long shot but what if i plan on switching to a 6.0l block in the future? Would the heads swap over alright? In that case would the 5.3ls be wasted?
I don't mind doing an engine swap if it's only the short block i need to replace, the long block gets awfully pricey for someone that's not a hardcore racer.
Also, this is a long shot but what if i plan on switching to a 6.0l block in the future? Would the heads swap over alright? In that case would the 5.3ls be wasted?
I don't mind doing an engine swap if it's only the short block i need to replace, the long block gets awfully pricey for someone that's not a hardcore racer.
09-22-2009, 02:38 PM
#6
Pretty sure the 5.3's would switch over, but would raise the compression even more than on a stock LS1.
I would go with 243's b/c of the flow if they are going on a 6.0 later on.
Also, in your first post you mentioned LS3,L92, etc heads. You cant use them on an LS1 b/c they need atleast a 4" bore b/c of the valves, so count them out.
I would go with 243's b/c of the flow if they are going on a 6.0 later on.
Also, in your first post you mentioned LS3,L92, etc heads. You cant use them on an LS1 b/c they need atleast a 4" bore b/c of the valves, so count them out.
09-22-2009, 04:59 PM
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5.3 stock heads are basically an ls1 (241 and similar) head with a smaller chamber (I think 63 or 62cc) and smaller intake valve (less than 2.00) and not sure on the exhaust valve
the tsp 5.3 stg 2.5 has cnc ports and 2.02/1.57 or 1.575 valves and double springs up to 650 lift
they will fit a 6.0 short block (many did it)
the price difference between 5.3 2.5 and ls6 2.5 is around 300$ and the later flows better but the 5.3 is not bad at all
compression between the two if all the same is the difference in chamber 62cc vs 64 or 65cc
will be about x.3:1
increased compression = more hp and tourque wether it`s by a smaller chamber or a thinner head gasket or milling the heads to have a certain chamber cc on the same engine given that it`s ok with the fuel octane you`re gonna use
might help you a little
the tsp 5.3 stg 2.5 has cnc ports and 2.02/1.57 or 1.575 valves and double springs up to 650 lift
they will fit a 6.0 short block (many did it)
the price difference between 5.3 2.5 and ls6 2.5 is around 300$ and the later flows better but the 5.3 is not bad at all
compression between the two if all the same is the difference in chamber 62cc vs 64 or 65cc
will be about x.3:1
increased compression = more hp and tourque wether it`s by a smaller chamber or a thinner head gasket or milling the heads to have a certain chamber cc on the same engine given that it`s ok with the fuel octane you`re gonna use
might help you a little
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09-22-2009, 06:29 PM
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Could I have the ls6's milled or use smaller gaskets on them and achieve similar results in regards to compression on the 5.3's? Or does that just make me run into PtV clearance issues?
09-22-2009, 08:35 PM
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ls3 heads won`t fit stock ls1 block because of the big intake valve and small bore in the block but will fit 6.0 L blocks
people mill 243 and even 5.3 heads and put slimmer head gaskets to acheive their desired compression that they can run on the fuel octane they`re using and the slimmer head gasket gives a better quench but I still don`t understand that well ^_^
ptv clearance with your cam needs some info like cam duration lift and lsa and what heads and valves sizes and how much milled and what thickness gaskets and that`s something I don`t know about .... and with your cam any stock head with 2.02 valve might have ptv issue as it`s not a stock head question anymore many big cams are designed for a safe ptv with a stock engine milled and bigger valves is something else that experts might know about with your cam
if you`re swapping heads then do valve relieves on your stock pistons and have a piece of mind weather you do it yourself using gides from what people wrote on older threads or have a shop do it.
this is what I know hope it helps or someone else carries over with what they know.
people mill 243 and even 5.3 heads and put slimmer head gaskets to acheive their desired compression that they can run on the fuel octane they`re using and the slimmer head gasket gives a better quench but I still don`t understand that well ^_^
ptv clearance with your cam needs some info like cam duration lift and lsa and what heads and valves sizes and how much milled and what thickness gaskets and that`s something I don`t know about .... and with your cam any stock head with 2.02 valve might have ptv issue as it`s not a stock head question anymore many big cams are designed for a safe ptv with a stock engine milled and bigger valves is something else that experts might know about with your cam
if you`re swapping heads then do valve relieves on your stock pistons and have a piece of mind weather you do it yourself using gides from what people wrote on older threads or have a shop do it.
this is what I know hope it helps or someone else carries over with what they know.
