First Gen LS conversion from 500ci BBC questions Lq4/408
06-29-2013, 07:41 AM
#1
First Gen LS conversion from 500ci BBC questions Lq4/408 New to LS guys but I think its time to get familiar, after using them in my Daily Drivers and helping with some Power Grid installs via a dyno shop further exposing me to them...frankly I find them irresistible as a project. Before I reveal what ive located I should probably tell you a little about my current combo.
It can be seen in my Signature but now its terribly mismatched with a Ultra 950HP bolted to a dominator intake with 3.55 gears and a fairly tight stall...managed a 6.76 in this trim but 60ft WAY of its normal. Through testing with the wideband reveals the carb doesnt respond very well to orifice changes at any phase of the circuits. In fact contrary to previous experience it leans down heavily when I add the air cleaner thereby leaving me to believe anything that slows the air down loses what little signal the huge venturi have. This is a result of the relationship to the huge 4500 intake vs the 4150 carb in addition to the cam. Since its a tall deck 4150 intake choice is very limited.
So im looking at a few options here.
1. Get some intake spacers buy and port a BBC RPM Air gap then use a slip collar dist. Bear in mind i would have to port the spacers to and getting an intake lined up right that works well with the engines new RPM range to effective ET will be hampered not only by the induction choice above the head but now the head itself becomes a liability. So in reality to match this combo up nicely would require a head pull, sell, and purchase of say AFR 300cc oval ports with either an RPM air gap or victor JR oval ported to it still having to trouble with spacer plates and slip collar dist. In addition the exhaust is actually a hot mess regardless of results or first appearances. Its all doable but what brings me to LS forum?
After a couple near death experiences and having my health reduced to living stuck in a house and wheelchair bound for 2 years my priorities have changed somewhat. Ive had my 1st gen Camaro since I was 19 ( now 41 ) and I want to get away from Strip with Some Street to real deal Street that I drive to the track occasionally. MY first step on this path was to pick up a 4l80e core that I dropped off this week at a trusted friends to get built. Now I will add this to either combo however Im currently running no power steering ( hard on me ) with a small vega style box to clear tall deck and raised exhaust port heads. In addition I do have a factory AC car with all the controls and inner vents still operational except air box removed. So its paramount to me at this stage in my life and health that a vintage air system gets retrofitted in there.
When I start looking at tall deck BBC accessory drives to support PS and AC coupled with the fact I really need a head swap and exhaust upgrade while still having huge variables of spacers for intake and slip collar dist adjustments it starts to become a fairly major and costly undertaking. Not to mention there is so little room on between fans, crossmember, and engine its comical. Add to this my health and leaning over working on huge tight fitting heavy tall deck BBC stuff is a real labor and concern.....
Enter the LS swap idea. I love the power, size, and dependability of the LS platform ive been raving for years about them in our trucks and cars. As I begin to discuss what I feel my options are bear in mind I need to right now buy Intake plus spacers ( 450 ), headers that actually fit and arent crushed ( 600 ) slip collar dist ( 285 ) and custom bbc td accessory drive ( 850 ). thats just to get basic combination closer but really a head pull, sell, and repurchase as well. Not to mention the engine is gapped for a 300shot I dont ever use.
My LS thoughts, questions and what ive located in a few scenarios for you to hopefully share your constructive thoughts on.
I have located a complete no major issues ( supposedly ) 6.0L pull out for $350. I have also located some 5364 L92 heads in good shape for $500 ( really surprised there arent more on here as people like me run them for cost constraints eventually stepping up to the good stuff ). Here is how I see my options tell me where im wrong or what im forgetting. Just a reminder I already have to buy 4l80e crossmember for current project as well as headers and accessory drive bare minimum.
1. Partial tear down and inspection of 6.0l updating rod bolts, oil pump, and installing felpro MLS with new bolts on the L92 heads. Swapping in new springs to match cam selection as I get the heads checked. Using a Victor JR l92 intake and my ultra hp 950 ( yes its to big but I can size in the correct one later ). It my understanding that with the factory piston valve reliefs and the L92 heads im very limited on cam sizing but just on my research there seems to be a very well known limit without fly cutting looks like mid 220/.580ish lift with some known cams. I plan to use a good 1 7/8th full long tube on any LS combo I build as I only want to do the exhaust once. this would be a really cheap option I could throw together fairly quickly and not rely on selling of old parts to augment. Im guessing 475 HP with this combo which would be anemic to what im used to even with the weight savings so at least a 150hp shot would have to be on tap. But it would get me up swapped in and running an LS to start learning and lining out with little risk.
2. Same 6.0, L92 heads, and L92 intake but full tear down buy new forged pistons and good rods with ARP 2000 bolts upgrade to head studs with felpro MLS. This would allow me to up the compression use pistons with deeper valve relieves thereby running larger cams. Initial research indicates the l92 head has a weak exhaust to intake flow ratio so im guessing something with more split to help the exhaust port out. In this trim with the larger cam I would expect that I could make 500-520hp and safely hold a little larger N20 shot or swap in a cheap 76mm turbo kit and not lose a ton of money if things go south....This would take me a little longer to build without downtime.
3. There one im leaning toward which will require either longer build time or downtime selling off current combo to fund. Same 6.0 tear down send to machine shop bored and associated work to get 4.003 pistons and 4.00 stroke crank in there. Decked to positive 005 for proper quench. Mill heads as required in combination with piston design to yield 11-11.5 max effort pump gas along with much larger cam to accommodate demands and DCR. Send the L92s out to get ported ( special attention paid to exhaust side ) Victor Jr l92 intake ect. at the reduced weight I feel like would be a 550-575hp combo conservatively that should replicate my current ETs while providing future options for N20 and Boost ( with head/gasket swaps to lower compression ). This would require me to sell off to complete but would be more in line with what im used to. Build cost would still be minimal for this type of power IF there are no major issues with my cheaply found 6.0 and 5364 cores?
There a few of my ideas what are my goals? True weekend warrior that I can AC and PS that with my current good suspension ( proven capable of holding 650ft/lbs but needing a few tweaks ) should be 1.3x-1.4x 60ft capable of running 7.0 in the heat with a 4l80e and lockup style 4500 converter ( most likely yank, circle d, or Pro Edge )....am I crazy or crazy like a fox ( killer that is ).....
If you read all that im guessing ill get some constructive advice HAHA....
It can be seen in my Signature but now its terribly mismatched with a Ultra 950HP bolted to a dominator intake with 3.55 gears and a fairly tight stall...managed a 6.76 in this trim but 60ft WAY of its normal. Through testing with the wideband reveals the carb doesnt respond very well to orifice changes at any phase of the circuits. In fact contrary to previous experience it leans down heavily when I add the air cleaner thereby leaving me to believe anything that slows the air down loses what little signal the huge venturi have. This is a result of the relationship to the huge 4500 intake vs the 4150 carb in addition to the cam. Since its a tall deck 4150 intake choice is very limited.
So im looking at a few options here.
1. Get some intake spacers buy and port a BBC RPM Air gap then use a slip collar dist. Bear in mind i would have to port the spacers to and getting an intake lined up right that works well with the engines new RPM range to effective ET will be hampered not only by the induction choice above the head but now the head itself becomes a liability. So in reality to match this combo up nicely would require a head pull, sell, and purchase of say AFR 300cc oval ports with either an RPM air gap or victor JR oval ported to it still having to trouble with spacer plates and slip collar dist. In addition the exhaust is actually a hot mess regardless of results or first appearances. Its all doable but what brings me to LS forum?
After a couple near death experiences and having my health reduced to living stuck in a house and wheelchair bound for 2 years my priorities have changed somewhat. Ive had my 1st gen Camaro since I was 19 ( now 41 ) and I want to get away from Strip with Some Street to real deal Street that I drive to the track occasionally. MY first step on this path was to pick up a 4l80e core that I dropped off this week at a trusted friends to get built. Now I will add this to either combo however Im currently running no power steering ( hard on me ) with a small vega style box to clear tall deck and raised exhaust port heads. In addition I do have a factory AC car with all the controls and inner vents still operational except air box removed. So its paramount to me at this stage in my life and health that a vintage air system gets retrofitted in there.
When I start looking at tall deck BBC accessory drives to support PS and AC coupled with the fact I really need a head swap and exhaust upgrade while still having huge variables of spacers for intake and slip collar dist adjustments it starts to become a fairly major and costly undertaking. Not to mention there is so little room on between fans, crossmember, and engine its comical. Add to this my health and leaning over working on huge tight fitting heavy tall deck BBC stuff is a real labor and concern.....
Enter the LS swap idea. I love the power, size, and dependability of the LS platform ive been raving for years about them in our trucks and cars. As I begin to discuss what I feel my options are bear in mind I need to right now buy Intake plus spacers ( 450 ), headers that actually fit and arent crushed ( 600 ) slip collar dist ( 285 ) and custom bbc td accessory drive ( 850 ). thats just to get basic combination closer but really a head pull, sell, and repurchase as well. Not to mention the engine is gapped for a 300shot I dont ever use.
My LS thoughts, questions and what ive located in a few scenarios for you to hopefully share your constructive thoughts on.
I have located a complete no major issues ( supposedly ) 6.0L pull out for $350. I have also located some 5364 L92 heads in good shape for $500 ( really surprised there arent more on here as people like me run them for cost constraints eventually stepping up to the good stuff ). Here is how I see my options tell me where im wrong or what im forgetting. Just a reminder I already have to buy 4l80e crossmember for current project as well as headers and accessory drive bare minimum.
1. Partial tear down and inspection of 6.0l updating rod bolts, oil pump, and installing felpro MLS with new bolts on the L92 heads. Swapping in new springs to match cam selection as I get the heads checked. Using a Victor JR l92 intake and my ultra hp 950 ( yes its to big but I can size in the correct one later ). It my understanding that with the factory piston valve reliefs and the L92 heads im very limited on cam sizing but just on my research there seems to be a very well known limit without fly cutting looks like mid 220/.580ish lift with some known cams. I plan to use a good 1 7/8th full long tube on any LS combo I build as I only want to do the exhaust once. this would be a really cheap option I could throw together fairly quickly and not rely on selling of old parts to augment. Im guessing 475 HP with this combo which would be anemic to what im used to even with the weight savings so at least a 150hp shot would have to be on tap. But it would get me up swapped in and running an LS to start learning and lining out with little risk.
2. Same 6.0, L92 heads, and L92 intake but full tear down buy new forged pistons and good rods with ARP 2000 bolts upgrade to head studs with felpro MLS. This would allow me to up the compression use pistons with deeper valve relieves thereby running larger cams. Initial research indicates the l92 head has a weak exhaust to intake flow ratio so im guessing something with more split to help the exhaust port out. In this trim with the larger cam I would expect that I could make 500-520hp and safely hold a little larger N20 shot or swap in a cheap 76mm turbo kit and not lose a ton of money if things go south....This would take me a little longer to build without downtime.
3. There one im leaning toward which will require either longer build time or downtime selling off current combo to fund. Same 6.0 tear down send to machine shop bored and associated work to get 4.003 pistons and 4.00 stroke crank in there. Decked to positive 005 for proper quench. Mill heads as required in combination with piston design to yield 11-11.5 max effort pump gas along with much larger cam to accommodate demands and DCR. Send the L92s out to get ported ( special attention paid to exhaust side ) Victor Jr l92 intake ect. at the reduced weight I feel like would be a 550-575hp combo conservatively that should replicate my current ETs while providing future options for N20 and Boost ( with head/gasket swaps to lower compression ). This would require me to sell off to complete but would be more in line with what im used to. Build cost would still be minimal for this type of power IF there are no major issues with my cheaply found 6.0 and 5364 cores?
There a few of my ideas what are my goals? True weekend warrior that I can AC and PS that with my current good suspension ( proven capable of holding 650ft/lbs but needing a few tweaks ) should be 1.3x-1.4x 60ft capable of running 7.0 in the heat with a 4l80e and lockup style 4500 converter ( most likely yank, circle d, or Pro Edge )....am I crazy or crazy like a fox ( killer that is ).....
If you read all that im guessing ill get some constructive advice HAHA....
06-29-2013, 08:05 AM
#2
Forgot to mention I hope to get at least a little better fuel economy. I have been leaning down the primary side of my ultra 950 for cruise and using a 6530 programmable MSD to replicate vacuum advance at cruise...I got it from 7mph up into double digits 
im sure the 4l80e is gonna help either combo on this front though...
im sure the 4l80e is gonna help either combo on this front though...
06-29-2013, 12:10 PM
#3
My thoughts are if you are looking for more street than strip, you should not mess with the 6.0 as you bought it. Just a thorogh inspection, and cleaning without tear down. Keep the OEM 317 heads as they are great heads. Pick a mild cam such as something around 230/230, 112+4lsa, and install matching dual valve springs/ seals. And run a Vic Jr intake, especially if you want to spray it in the future.
Drive it like that , and even spray it a bit, untill you decide to build it up for further performance.
The 950hp carb is ANSOLUTELY NOT too big, RUN IT!!
You will want a 3000 or higher stall depending on cam.
This engine combo with a decently good working car will be capable of 7.0's in the quarter at about 96+/- mph, possibly even faster.
An MSD 6010/6012 ignition is programmable and is your best option, it can run a map sensor to to build a 3d timing curve based on vacuum/ rpm.
Drive it like that , and even spray it a bit, untill you decide to build it up for further performance.
The 950hp carb is ANSOLUTELY NOT too big, RUN IT!!
You will want a 3000 or higher stall depending on cam.
This engine combo with a decently good working car will be capable of 7.0's in the quarter at about 96+/- mph, possibly even faster.
An MSD 6010/6012 ignition is programmable and is your best option, it can run a map sensor to to build a 3d timing curve based on vacuum/ rpm.
Last edited by 3pedals; 06-29-2013 at 12:21 PM.
06-29-2013, 01:35 PM
#4
To save cash, use the 6.0 as is as above with a custom grind cam. Leave the heads on it. My 89 RS was 7.1s all day with a manual Trans at 3450 lbs with me in the car. Best time was a 7.0. A auto with proper converter should have went sub 7.0, but I was hitting 1.5 60s.
A little greedy would lead to the l92 heads and max greedy would lead to the 408 build.
A little greedy would lead to the l92 heads and max greedy would lead to the 408 build.
07-11-2013, 09:51 PM
#5
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I agree with them that I'd run the 6.0L as is for awhile with just a cam & valvespring swap. I would go ahead and snag those L92 heads now while you can and just hang on to them for round two.
Where are you located and what are you going to do with your 505" parts?
Where are you located and what are you going to do with your 505" parts?
