LS6 Valves In 081 Heads During Rebuild
Thread Starter
Joined: Feb 2008
Posts: 567
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Car: 1987 GTA Vert & 1991 GTA 5 Speed
Engine: 87 GTA-L98 91 GTA LB9
Transmission: GTA-700R4 & GTA T5
LS6 Valves In 081 Heads During Rebuild
I am about to pull the trigger on a rebuild on my GTA. I have been looking at some inexpensive MODs I can do to the little LB9 while rebuilding it. Any suggestions would be helpful. So far I have
- Dyno Dons headers and y-pipe with dual exhaust
-ZZ4 cam
-LS6 titaniun valves
-LS6 Yellow beehive springs
When the engine is disassembled at the end of the month I will begin the DIY porting on the upper and lower intake and head work.
I found this thread while searching for cheap MODs for the LB9.
https://www.thirdgen.org/forums/tech-general-engine/336363-ls1-valves-springs-l98.html
I have the valves and springs as you see above. I now need to get the retainers and valve locks. I need some help figuring out which ones to get. I am not sure which ones to order.
Last edited by Slowridr; Mar 19, 2016 at 06:54 PM.
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Re: LS6 Valves In 081 Heads During Rebuild
Comp 787 are for small block Chevy valves (11/32" dia) using LSx valve springs.
You're gonna be looking at A CHUNK of $$$$$$$ to put LSx valves into your heads. But, if you do that, stock LSx retainers and keepers will do the trick.
Personally, I wouldn't bother putting that kind of $$$ into a 305. After it's all done, you'll still be stuck with ... a 305. Even worse, with TPI on it. With a cam NOT particularly well suited to TPI. Even if you don't make that mistake, you still basically won't be able to even detect any difference all that $$$$$$$$ made.
The springs, yes; the valves and the $$$$$ machine work, not worth it.
You're gonna be looking at A CHUNK of $$$$$$$ to put LSx valves into your heads. But, if you do that, stock LSx retainers and keepers will do the trick.
Personally, I wouldn't bother putting that kind of $$$ into a 305. After it's all done, you'll still be stuck with ... a 305. Even worse, with TPI on it. With a cam NOT particularly well suited to TPI. Even if you don't make that mistake, you still basically won't be able to even detect any difference all that $$$$$$$$ made.
The springs, yes; the valves and the $$$$$ machine work, not worth it.
Last edited by sofakingdom; Mar 19, 2016 at 08:54 PM.
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Car: Fourth Gen '94 camaro
Engine: 350 Gen II
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Re: LS6 Valves In 081 Heads During Rebuild
Those 2.1" LS6 vlvs and seats ain't gonna fit in a L98 head let alone a 3.75" bore 305/LB9. Better off just buying the Trick Flow heads for a 305" motor with vlvs that will fit.
Joined: Sep 2005
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Re: LS6 Valves In 081 Heads During Rebuild
If you're gonna spend wads of money, better off spending it on something else besides a 305 in the first place.
Remember: Fun = $$$ x CID
If CID is small, Fun will be as well.
Remember: Fun = $$$ x CID
If CID is small, Fun will be as well.
Thread Starter
Joined: Feb 2008
Posts: 567
Likes: 14
Car: 1987 GTA Vert & 1991 GTA 5 Speed
Engine: 87 GTA-L98 91 GTA LB9
Transmission: GTA-700R4 & GTA T5
Re: LS6 Valves In 081 Heads During Rebuild
I completely understand on the Fun equation you shared above but I want to keep the LB9 in this Convertible. I imagine I could do some things to beef up the frame to handle more hp but Ill save my high power build for my 91 GTA. Im hoping to start on that next year.
Also I guess I should have provided more info regarding the valves. Here is a post from that thread I referred to above.
Originally posted by 1991CamaroRslow*
" 305sbc you have actually done this setup, do you think it's worth the effort?
Yes I do think it's worth the effort. I recently got a used set of LS1 valves, retainers, keepers, and springs for $40 on ebay. The LS1 valves are much better quality pieces than stock L98, not to mention better flowing and lighter in weight. They are usually low miles and I've not noticed any wear problems. It may have to do with the fact that LS1 heads come from the factory with very nice bronze guides. Valves coming out of iron heads w/iron guides seem to show more wear.*
I would only run the stock LS1 springs in a stock or very mild application. If you look over the spring data you can see why I'd prefer the 918's for a performance application. If you're keeping the lift down to .500" or lower then the stock LS1 springs should be fine. I like to have a little more pressure on the seat for an aggressive cam lobe than the stock LS1 springs offer. The Z06 springs are much better and allow more lift. If you look around you can get these at reasonable cost.
The new design 918's can easily go over .700" lift if you cut the spring pockets .050" deeper.
Another option is to use the lightweight 2002 and up Z06 valves.
intake: 73 grams
exhaust: 65 grams
These can be had for $220 new from certain places. This doesn't sound cheap, but for what they are it's a good deal. These are lighter than most titanium valves.
__________________________________
If you're looking for more RPM then this swap offers lighter valvetrain parts along with a conical spring.
If you're looking for flow, this swap offers larger valve head area along with a smaller 8mm -0.314" stem. Factory type 23* heads flow air primarily across the back of the valve, so the LS1 valve has a nice advantage in head shape and the thinner stem. A flat backed valve is the best choice for the older factory iron heads using moderate valve lifts.*
The small size and shape of the LS1 retainer leaves lots of clearance for the beefy rockers. This helps out those people who prefer to run a pushrod on the short side. It's also lighter weight than most titanium retainers. The LS1 steel retainer and keepers combo weighs 13.5 grams.
As for parts upgrade this swap would be tough to beat for the cost. If combined with good porting to match the valves, the flow potential is great.
By the way my valves for the GTA Convertible build are 2.00 intake and 1.55 exhaust.
Last edited by Slowridr; Mar 20, 2016 at 09:23 AM.
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Re: LS6 Valves In 081 Heads During Rebuild
That entire write-up is deeply flawed. I don't agree with ONE SINGLE WORD of it..
Note also, it doesn't say A DAMN WORD about "this is what I DID, and this is what HAPPENED". It's all about "I bought on ebay" and "would run" and such as that. For all we can tell, d00d has NEVER EVEN ACTUALLY DONE what he's talking about, to find out how well it works. (or not?)
To put LS1 valves in 081 heads, the chamber has to be opened up SUBSTANTIALLY, especially on the intake side. One look at what will happen when you enlarge the valves, should be enough to show why. The "vertical" wall of the chamber is right close to the margin of the valve; the incoming cyl fill charge flows along the "common" wall of the port, the one where the 2 intake ports are adjacent to each other; that wall lines up with the side of the port in question; and it doesn't particularly matter how large you make the valve, or even how well you make the port flow, if the incoming material all has to squeeeeeeze through a little crack over there. But then, if you lay that wall back, you add cc's to the chamber, meaning your compression goes down. It's a lose-lose situation.
Worse, the cyl bore has THE EXACT SAME effect. As the valve continues to open further (i.e. as you increase the lift) the valve margin passes the chamber and descends into the bore. Since the 305 bore is so small, the valve ends up RIGHT NEXT TO the cyl wall... once again, totally shrouding the high-flow part of the port. You can even end up with a situation, depending on how accurate the dowel pins are drilled into the block and how accurate the valve guides are located, where the valve doesn't even fit into the cyl, but rather hits the top of the block.
Then on top of that, the LSx valves have a thinner stem, which means significant surgery to install them. The valve guides have to be replaced with ones that fit the foreign valves.
So in the end, for a 305, you end up spending ALL THIS MONEY, only to go BACKWARDS in terms of performance AT BEST, and potentially create a mess that WON'T EVEN OPERATE, at worst.
Now if you had a 350 or 400 block, with a large enough bore to avoid shrouding from that, and enough CID to tolerate the increase in chamber size, AND free access to the services of a machine shop, AND some other intake system besides TPI, it might be a different matter. But if not, then you're taking your own money and using it as the weapon to shoot yourself in the shorts.
The 918 spring AFAIK is discontinued. Try finding it in Comp's catalog. Try looking up CCA-918-16 on Summit.
LSx springs, Comp 787 retainers, and the Comp standard 601 or the upgrade 648 keepers, with your existing valves, is the way to go. Assuming of course you use NEW springs, not wore-out used-up stockers. I would recommend these. http://www.texas-speed.com/p-4406-pa...e-springs.aspx The 1218 specifically.
Meanwhile the logic of spending all this money with the apparent and stated goal of improving performance, while at the same time, talking about weeeeek frame and all that, is not obvious.
All in all, sounds like you need to do a bit more research than to just swallow whole a seriously flawed and/or obsolete write-up from some ONE yutz on the Internet, who was in fact talking about SOME OTHER engine, just because it tells you what you think you want to hear. And above all, understand that (a) TPI and (b) 305, especially TOGETHER, create a situation that DEFEATS performance. Either one by itself is bad enough; the 2 together pretty much guarantee that there is ZERO potential for improved power beyond what can be obtained by replacing the exhaust. (which IS a good mod, for ANY size motor... not least because, when you realize that the 305 is a waste, you don't have to throw it away and start over)
If you want to swap the cam, the ZZ4 cam is a poor choice. Look instead at the Comp "501" grind http://www.summitracing.com/parts/cca-08-501-8. It's a MUCH better match to the rather unique requirements that TPI places on cam design, than the other.
Note also, it doesn't say A DAMN WORD about "this is what I DID, and this is what HAPPENED". It's all about "I bought on ebay" and "would run" and such as that. For all we can tell, d00d has NEVER EVEN ACTUALLY DONE what he's talking about, to find out how well it works. (or not?)
To put LS1 valves in 081 heads, the chamber has to be opened up SUBSTANTIALLY, especially on the intake side. One look at what will happen when you enlarge the valves, should be enough to show why. The "vertical" wall of the chamber is right close to the margin of the valve; the incoming cyl fill charge flows along the "common" wall of the port, the one where the 2 intake ports are adjacent to each other; that wall lines up with the side of the port in question; and it doesn't particularly matter how large you make the valve, or even how well you make the port flow, if the incoming material all has to squeeeeeeze through a little crack over there. But then, if you lay that wall back, you add cc's to the chamber, meaning your compression goes down. It's a lose-lose situation.
Worse, the cyl bore has THE EXACT SAME effect. As the valve continues to open further (i.e. as you increase the lift) the valve margin passes the chamber and descends into the bore. Since the 305 bore is so small, the valve ends up RIGHT NEXT TO the cyl wall... once again, totally shrouding the high-flow part of the port. You can even end up with a situation, depending on how accurate the dowel pins are drilled into the block and how accurate the valve guides are located, where the valve doesn't even fit into the cyl, but rather hits the top of the block.
Then on top of that, the LSx valves have a thinner stem, which means significant surgery to install them. The valve guides have to be replaced with ones that fit the foreign valves.
So in the end, for a 305, you end up spending ALL THIS MONEY, only to go BACKWARDS in terms of performance AT BEST, and potentially create a mess that WON'T EVEN OPERATE, at worst.
Now if you had a 350 or 400 block, with a large enough bore to avoid shrouding from that, and enough CID to tolerate the increase in chamber size, AND free access to the services of a machine shop, AND some other intake system besides TPI, it might be a different matter. But if not, then you're taking your own money and using it as the weapon to shoot yourself in the shorts.
The 918 spring AFAIK is discontinued. Try finding it in Comp's catalog. Try looking up CCA-918-16 on Summit.
LSx springs, Comp 787 retainers, and the Comp standard 601 or the upgrade 648 keepers, with your existing valves, is the way to go. Assuming of course you use NEW springs, not wore-out used-up stockers. I would recommend these. http://www.texas-speed.com/p-4406-pa...e-springs.aspx The 1218 specifically.
Meanwhile the logic of spending all this money with the apparent and stated goal of improving performance, while at the same time, talking about weeeeek frame and all that, is not obvious.
All in all, sounds like you need to do a bit more research than to just swallow whole a seriously flawed and/or obsolete write-up from some ONE yutz on the Internet, who was in fact talking about SOME OTHER engine, just because it tells you what you think you want to hear. And above all, understand that (a) TPI and (b) 305, especially TOGETHER, create a situation that DEFEATS performance. Either one by itself is bad enough; the 2 together pretty much guarantee that there is ZERO potential for improved power beyond what can be obtained by replacing the exhaust. (which IS a good mod, for ANY size motor... not least because, when you realize that the 305 is a waste, you don't have to throw it away and start over)
If you want to swap the cam, the ZZ4 cam is a poor choice. Look instead at the Comp "501" grind http://www.summitracing.com/parts/cca-08-501-8. It's a MUCH better match to the rather unique requirements that TPI places on cam design, than the other.
Last edited by sofakingdom; Mar 20, 2016 at 09:52 AM.
Member
Joined: Aug 2010
Posts: 478
Likes: 4
From: Las Vegas
Car: Fourth Gen '94 camaro
Engine: 350 Gen II
Transmission: A4
Axle/Gears: 3.23
Re: LS6 Valves In 081 Heads During Rebuild
Slowridr, your using information in bits and pieces from all over the place but not anything that works together. Your original post was for LS6 vlvs and now u are talking LS1 vlvs. Well my understanding even the smaller 2.00"/1.55" LS1/LQ4 vlvs wont fit inside the small 3.75" bore of the LB9 - at the original 23 degree vlv angle. U are limited to 1.94" vlvs for that 23* head and 3.75" bore.
Something else is that even though the lighter vlvs do allow for weaker vlv springs most running the TPI induction dont run high enough rpm to require a lighter vlv train. Though u may have different rpm goals power will drop fast at high rpm w/stock TPI induction.
Pocket porting the stock heads with a good multi-angle vlv job will be your best bang for the buck. Build w/good quench and u can run compression up to 9.5 c.r. for more torque and throttle response.
To spread out the peaky power band of the TPI i would install a cam with a wider lobe seperation angle like 112 or 114. Also a Tri-Y or stepped header will help distribute the power band better than standard long tube headers. Im not sure if shorty headers would give u much improvement unless u can run at very high RPM so rather than experiment i recommend Tri-Y or stepped headers for the TPI induction.
I guess what im saying is i would optimize the motor around the TPI induction rather than chase unproven inovations like larger vlvs that doubtful can even fit.
BTW i have considered using the LS1/LQ4 vlvs also but in the LT1 head with larger bores in the block. But once u look at the cost of brand new vlvs compared to the time digging into used heads at the juck yard and installing new vlv guides, retainers just for used vlvs its kinda a losing effort. Just a cool idea to u and me - thats it though.
Something else is that even though the lighter vlvs do allow for weaker vlv springs most running the TPI induction dont run high enough rpm to require a lighter vlv train. Though u may have different rpm goals power will drop fast at high rpm w/stock TPI induction.
Pocket porting the stock heads with a good multi-angle vlv job will be your best bang for the buck. Build w/good quench and u can run compression up to 9.5 c.r. for more torque and throttle response.
To spread out the peaky power band of the TPI i would install a cam with a wider lobe seperation angle like 112 or 114. Also a Tri-Y or stepped header will help distribute the power band better than standard long tube headers. Im not sure if shorty headers would give u much improvement unless u can run at very high RPM so rather than experiment i recommend Tri-Y or stepped headers for the TPI induction.
I guess what im saying is i would optimize the motor around the TPI induction rather than chase unproven inovations like larger vlvs that doubtful can even fit.
BTW i have considered using the LS1/LQ4 vlvs also but in the LT1 head with larger bores in the block. But once u look at the cost of brand new vlvs compared to the time digging into used heads at the juck yard and installing new vlv guides, retainers just for used vlvs its kinda a losing effort. Just a cool idea to u and me - thats it though.
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Thread Starter
Joined: Feb 2008
Posts: 567
Likes: 14
Car: 1987 GTA Vert & 1991 GTA 5 Speed
Engine: 87 GTA-L98 91 GTA LB9
Transmission: GTA-700R4 & GTA T5
Re: LS6 Valves In 081 Heads During Rebuild
That entire write-up is deeply flawed. I don't agree with ONE SINGLE WORD of it..
Note also, it doesn't say A DAMN WORD about "this is what I DID, and this is what HAPPENED". It's all about "I bought on ebay" and "would run" and such as that. For all we can tell, d00d has NEVER EVEN ACTUALLY DONE what he's talking about, to find out how well it works. (or not?)
To put LS1 valves in 081 heads, the chamber has to be opened up SUBSTANTIALLY, especially on the intake side. One look at what will happen when you enlarge the valves, should be enough to show why. The "vertical" wall of the chamber is right close to the margin of the valve; the incoming cyl fill charge flows along the "common" wall of the port, the one where the 2 intake ports are adjacent to each other; that wall lines up with the side of the port in question; and it doesn't particularly matter how large you make the valve, or even how well you make the port flow, if the incoming material all has to squeeeeeeze through a little crack over there. But then, if you lay that wall back, you add cc's to the chamber, meaning your compression goes down. It's a lose-lose situation.
Worse, the cyl bore has THE EXACT SAME effect. As the valve continues to open further (i.e. as you increase the lift) the valve margin passes the chamber and descends into the bore. Since the 305 bore is so small, the valve ends up RIGHT NEXT TO the cyl wall... once again, totally shrouding the high-flow part of the port. You can even end up with a situation, depending on how accurate the dowel pins are drilled into the block and how accurate the valve guides are located, where the valve doesn't even fit into the cyl, but rather hits the top of the block.
Then on top of that, the LSx valves have a thinner stem, which means significant surgery to install them. The valve guides have to be replaced with ones that fit the foreign valves.
So in the end, for a 305, you end up spending ALL THIS MONEY, only to go BACKWARDS in terms of performance AT BEST, and potentially create a mess that WON'T EVEN OPERATE, at worst.
Now if you had a 350 or 400 block, with a large enough bore to avoid shrouding from that, and enough CID to tolerate the increase in chamber size, AND free access to the services of a machine shop, AND some other intake system besides TPI, it might be a different matter. But if not, then you're taking your own money and using it as the weapon to shoot yourself in the shorts.
The 918 spring AFAIK is discontinued. Try finding it in Comp's catalog. Try looking up CCA-918-16 on Summit.
LSx springs, Comp 787 retainers, and the Comp standard 601 or the upgrade 648 keepers, with your existing valves, is the way to go. Assuming of course you use NEW springs, not wore-out used-up stockers. I would recommend these. http://www.texas-speed.com/p-4406-pa...e-springs.aspx The 1218 specifically.
Meanwhile the logic of spending all this money with the apparent and stated goal of improving performance, while at the same time, talking about weeeeek frame and all that, is not obvious.
All in all, sounds like you need to do a bit more research than to just swallow whole a seriously flawed and/or obsolete write-up from some ONE yutz on the Internet, who was in fact talking about SOME OTHER engine, just because it tells you what you think you want to hear. And above all, understand that (a) TPI and (b) 305, especially TOGETHER, create a situation that DEFEATS performance. Either one by itself is bad enough; the 2 together pretty much guarantee that there is ZERO potential for improved power beyond what can be obtained by replacing the exhaust. (which IS a good mod, for ANY size motor... not least because, when you realize that the 305 is a waste, you don't have to throw it away and start over)
If you want to swap the cam, the ZZ4 cam is a poor choice. Look instead at the Comp "501" grind http://www.summitracing.com/parts/cca-08-501-8. It's a MUCH better match to the rather unique requirements that TPI places on cam design, than the other.
Note also, it doesn't say A DAMN WORD about "this is what I DID, and this is what HAPPENED". It's all about "I bought on ebay" and "would run" and such as that. For all we can tell, d00d has NEVER EVEN ACTUALLY DONE what he's talking about, to find out how well it works. (or not?)
To put LS1 valves in 081 heads, the chamber has to be opened up SUBSTANTIALLY, especially on the intake side. One look at what will happen when you enlarge the valves, should be enough to show why. The "vertical" wall of the chamber is right close to the margin of the valve; the incoming cyl fill charge flows along the "common" wall of the port, the one where the 2 intake ports are adjacent to each other; that wall lines up with the side of the port in question; and it doesn't particularly matter how large you make the valve, or even how well you make the port flow, if the incoming material all has to squeeeeeeze through a little crack over there. But then, if you lay that wall back, you add cc's to the chamber, meaning your compression goes down. It's a lose-lose situation.
Worse, the cyl bore has THE EXACT SAME effect. As the valve continues to open further (i.e. as you increase the lift) the valve margin passes the chamber and descends into the bore. Since the 305 bore is so small, the valve ends up RIGHT NEXT TO the cyl wall... once again, totally shrouding the high-flow part of the port. You can even end up with a situation, depending on how accurate the dowel pins are drilled into the block and how accurate the valve guides are located, where the valve doesn't even fit into the cyl, but rather hits the top of the block.
Then on top of that, the LSx valves have a thinner stem, which means significant surgery to install them. The valve guides have to be replaced with ones that fit the foreign valves.
So in the end, for a 305, you end up spending ALL THIS MONEY, only to go BACKWARDS in terms of performance AT BEST, and potentially create a mess that WON'T EVEN OPERATE, at worst.
Now if you had a 350 or 400 block, with a large enough bore to avoid shrouding from that, and enough CID to tolerate the increase in chamber size, AND free access to the services of a machine shop, AND some other intake system besides TPI, it might be a different matter. But if not, then you're taking your own money and using it as the weapon to shoot yourself in the shorts.
The 918 spring AFAIK is discontinued. Try finding it in Comp's catalog. Try looking up CCA-918-16 on Summit.
LSx springs, Comp 787 retainers, and the Comp standard 601 or the upgrade 648 keepers, with your existing valves, is the way to go. Assuming of course you use NEW springs, not wore-out used-up stockers. I would recommend these. http://www.texas-speed.com/p-4406-pa...e-springs.aspx The 1218 specifically.
Meanwhile the logic of spending all this money with the apparent and stated goal of improving performance, while at the same time, talking about weeeeek frame and all that, is not obvious.
All in all, sounds like you need to do a bit more research than to just swallow whole a seriously flawed and/or obsolete write-up from some ONE yutz on the Internet, who was in fact talking about SOME OTHER engine, just because it tells you what you think you want to hear. And above all, understand that (a) TPI and (b) 305, especially TOGETHER, create a situation that DEFEATS performance. Either one by itself is bad enough; the 2 together pretty much guarantee that there is ZERO potential for improved power beyond what can be obtained by replacing the exhaust. (which IS a good mod, for ANY size motor... not least because, when you realize that the 305 is a waste, you don't have to throw it away and start over)
If you want to swap the cam, the ZZ4 cam is a poor choice. Look instead at the Comp "501" grind http://www.summitracing.com/parts/cca-08-501-8. It's a MUCH better match to the rather unique requirements that TPI places on cam design, than the other.
I have searched and found threads that have discussed the issues brought up regarding larger valves in 305 heads. The man that you are insulting has rebuilt 305 heads and has pictures on this forum with these valves installed. I contacted him prior to starting this thread and he stands behind what he has said about the performance. There is a premise behind doing this modification which he explains and it may not be useful for every situation. I like it for mine but am still seeking opinions from others about it and the parts involved. I have began collecting parts and if I get an opinion that would cause me to change direction I would not hesitate. Insults wont be the thing that will change mind but technical info will thats why I post the questions that I post.
Joined: Sep 2005
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Re: LS6 Valves In 081 Heads During Rebuild
Not sure who "insulted" whom; pretty sure it wasn't me that either insulted anybody or got insulted myself; but you'll have a pretty tough time getting unbiased technical help with an "I already know everything and you can't tell me anything" attitude about a bunch of mistakes and misguided fantasy-land "plans" like you're posting about.
Anybody can jam just about any valves into just about any heads. Just because it "can be done", doesn't automatically make it "A Good Idea". Doesn't even mean that it will FIT in any given motor, let alone WORK, much less WORK BETTER than something else. (I note that you said these valves are "in" 305 HEADS, but fail to mention what size motor, IF ANY, they have ever been installed on) Even if it IS what you're wanting to hear.
I told you where a number of the flaws in the "plans" are. If you're not willing to LOOK AT things and see what I'm talking about, you're in for a rough ride as you spend your $$$$money$$$$ and it doesn't happen like you "planned".
Good luck with your project. Don't say you weren't warned when it causes more trouble than you ever dreamed it would, and fails altogether to live up to expectations in the unlikely case it ever does in fact live.
Anybody can jam just about any valves into just about any heads. Just because it "can be done", doesn't automatically make it "A Good Idea". Doesn't even mean that it will FIT in any given motor, let alone WORK, much less WORK BETTER than something else. (I note that you said these valves are "in" 305 HEADS, but fail to mention what size motor, IF ANY, they have ever been installed on) Even if it IS what you're wanting to hear.
I told you where a number of the flaws in the "plans" are. If you're not willing to LOOK AT things and see what I'm talking about, you're in for a rough ride as you spend your $$$$money$$$$ and it doesn't happen like you "planned".
Good luck with your project. Don't say you weren't warned when it causes more trouble than you ever dreamed it would, and fails altogether to live up to expectations in the unlikely case it ever does in fact live.
Last edited by sofakingdom; Mar 20, 2016 at 04:19 PM.
Thread Starter
Joined: Feb 2008
Posts: 567
Likes: 14
Car: 1987 GTA Vert & 1991 GTA 5 Speed
Engine: 87 GTA-L98 91 GTA LB9
Transmission: GTA-700R4 & GTA T5
Re: LS6 Valves In 081 Heads During Rebuild
Slowridr, your using information in bits and pieces from all over the place but not anything that works together. Your original post was for LS6 vlvs and now u are talking LS1 vlvs. Well my understanding even the smaller 2.00"/1.55" LS1/LQ4 vlvs wont fit inside the small 3.75" bore of the LB9 - at the original 23 degree vlv angle. U are limited to 1.94" vlvs for that 23* head and 3.75" bore.
Something else is that even though the lighter vlvs do allow for weaker vlv springs most running the TPI induction dont run high enough rpm to require a lighter vlv train. Though u may have different rpm goals power will drop fast at high rpm w/stock TPI induction.
Pocket porting the stock heads with a good multi-angle vlv job will be your best bang for the buck. Build w/good quench and u can run compression up to 9.5 c.r. for more torque and throttle response.
To spread out the peaky power band of the TPI i would install a cam with a wider lobe seperation angle like 112 or 114. Also a Tri-Y or stepped header will help distribute the power band better than standard long tube headers. Im not sure if shorty headers would give u much improvement unless u can run at very high RPM so rather than experiment i recommend Tri-Y or stepped headers for the TPI induction.
I guess what im saying is i would optimize the motor around the TPI induction rather than chase unproven inovations like larger vlvs that doubtful can even fit.
BTW i have considered using the LS1/LQ4 vlvs also but in the LT1 head with larger bores in the block. But once u look at the cost of brand new vlvs compared to the time digging into used heads at the juck yard and installing new vlv guides, retainers just for used vlvs its kinda a losing effort. Just a cool idea to u and me - thats it though.
Something else is that even though the lighter vlvs do allow for weaker vlv springs most running the TPI induction dont run high enough rpm to require a lighter vlv train. Though u may have different rpm goals power will drop fast at high rpm w/stock TPI induction.
Pocket porting the stock heads with a good multi-angle vlv job will be your best bang for the buck. Build w/good quench and u can run compression up to 9.5 c.r. for more torque and throttle response.
To spread out the peaky power band of the TPI i would install a cam with a wider lobe seperation angle like 112 or 114. Also a Tri-Y or stepped header will help distribute the power band better than standard long tube headers. Im not sure if shorty headers would give u much improvement unless u can run at very high RPM so rather than experiment i recommend Tri-Y or stepped headers for the TPI induction.
I guess what im saying is i would optimize the motor around the TPI induction rather than chase unproven inovations like larger vlvs that doubtful can even fit.
BTW i have considered using the LS1/LQ4 vlvs also but in the LT1 head with larger bores in the block. But once u look at the cost of brand new vlvs compared to the time digging into used heads at the juck yard and installing new vlv guides, retainers just for used vlvs its kinda a losing effort. Just a cool idea to u and me - thats it though.
Your first comment about these valves not fitting I addressed in my response to Sofa. The guy that has this MOD said that 2002 and later LS6 valves work as well. The valves that I purchased were listed as LS1/LS6 valves. I am trying to contact another person now that has done this for another opinion on the results but it has been done.
I agree and have read the same regarding pocket porting. I plan on doing that.
On the cam I got a great deal on a take out ZZ4 cam. From the threads I have read on the ZZ4 in the LB9 those that have installed it have been happy and were recommending it to those considering it as a MOD. What kind of gains performance wise are you talking about with the cam you are recommneding? The price and performance gain would have to be really good to beat the deal I got on this ZZ4.
Regarding the headers I wouldn't be against tri-y. Thats SLP correct? I got a great deal on these Dyno Dons so I am happy with those. I know that I will realize a hp gain so I will be happy with that even if its not as much as tri-ys.
I was explaining in my response to Sofa that the main premise behind the valve MOD is that the valves are going to be changed anyway. When changing the valves new guides are going to be installed so the only extra expense is the cost of the valves and the modifications needed to make them fit. From what was said.by the guy that did this there are flow gains to be had and again these 2.00/1.55 valves fit the 081 heads. Now if the guy is telling lies then we have a different situation. I dont sense he is lying here. Like I said before he has posted pics with the rebuilt heads and others have done this MOD. I'm trying to contact them now.
You and Sofa have brought some good technical info to the table and I appreciate that. My basic goal will not change however, I will be installing the original LB9 back into this car. If I can get some cheap power here or there then great Im not afraid to do it. If the logic is off Im not offended by comments stating that I just want to keep everything technical and on point which you have done. Thanks
Joined: Jul 2000
Posts: 6,519
Likes: 91
From: Aridzona
Car: `86 SS / `87 SS
Engine: L69 w/ TPI on top / 305 4bbl
Transmission: `95 T56 \ `88 200-4R
Re: LS6 Valves In 081 Heads During Rebuild
I've wasted some time on projects.
Camming an LB9 is one of the biggest ones.
Buy a mild cam that at least two wise people agree will help your combo. Meeting the budget in your head doesn't help your combo. Creating lift an duration that's only helpful at high rpm doesn't help an LB9.
You can re-use original roller lifters sometimes.
Your parts selection ability is not sage. Valves from an LS engine aren't better for an LB9. Valves that fit the LB9 and meet flow needs of a mild replacement cam and the choke choke choke choke long runner intake are all that's needed.
Keep in mind, Black Sabbath went into a time machine and recorded the throttle body sounds of an early 1984 prototype L98 at 4800rpm to record the beginning 6 seconds of Sweet Leaf. (that was for sofa. your translation is): You're not going to easily get performance from the LB9. If your goals later are bigger power, don't dump money into this LB9 situation unless the parts can 100% be used on a future build or sold (headers and roller rockers are like this. 305-LB9 friendly cams are not.)
Good luck.
Camming an LB9 is one of the biggest ones.
Buy a mild cam that at least two wise people agree will help your combo. Meeting the budget in your head doesn't help your combo. Creating lift an duration that's only helpful at high rpm doesn't help an LB9.
You can re-use original roller lifters sometimes.
Your parts selection ability is not sage. Valves from an LS engine aren't better for an LB9. Valves that fit the LB9 and meet flow needs of a mild replacement cam and the choke choke choke choke long runner intake are all that's needed.
Keep in mind, Black Sabbath went into a time machine and recorded the throttle body sounds of an early 1984 prototype L98 at 4800rpm to record the beginning 6 seconds of Sweet Leaf. (that was for sofa. your translation is): You're not going to easily get performance from the LB9. If your goals later are bigger power, don't dump money into this LB9 situation unless the parts can 100% be used on a future build or sold (headers and roller rockers are like this. 305-LB9 friendly cams are not.)
Good luck.
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