View Full Version : L92's, buy bare or complete for high lift cam?


tennerv8
09-30-2008, 02:40 PM
I want to get a set of L92's for a future build. I want to run a larger lift cam (closer to 600 lift). Is it cheaper to buy the heads bare for $200 each and then buy the valves and related parts and higher lift valve springs? Or do I buy the complete L92's for $400 each and then just buy higher lift valve springs? This is a low buck build so if I could save a few bucks that would be sweet. Thanks fellas.

camarols1
10-01-2008, 05:52 PM
What is the intended usage of the vehicle?

For a n/a build, the assembled L92's with a spring upgrade to match the cam would be the most economical.
As long as you are keeping a reasonable max RPM in mind, the stock valves would be ok.

On the other hand, a max effort FI build would benefit from a set of higher quality valves so it would make more sense to buy the heads bare.
No sense in buying parts that will not be used.

ItsNotStock
10-01-2008, 06:04 PM
Definately buy them assembled. You don't want to know what even the stock valves cost...

tennerv8
10-02-2008, 09:42 AM
Yeah I just want to do a inexpensive carb build-up to thrash on. I will not be reving it much past 7 grand. I think I will get them already assembled. Whats a good behive spring to get? My cam will have a max lift of .573 Could I get by with some sort of beehives?

camarols1
10-02-2008, 12:47 PM
Cheap springs = Valve float, broken valves, trashed short block.

Don't skimp here or you will be shopping for a short block next time.
I would not think of spinning 7k+ with the stock L92 valves and cheap springs.
The LS3 hollow stem intakes would be ok with a quality beehive, but the stock L92 valves are heavy and require a quality spring to keep the valves under control.
Also, the lobe design of the cam will affect the max RPM quite a bit.
If you use a less agressive lobe design the valvetrain will be more stable at RPM, but you will leave some power on the table.
Budget builds and 7k+ redlines don't go together very well, at least not for long.
If you build it right the first time you will be better off in the long run.

The Patriot duals would be a very smart investment.

camarols1
10-02-2008, 01:03 PM
FYI ~

The hollow stem LS3 intake valves (GM#12569427) are only about $160 for all eight.

jay_lt4
10-02-2008, 04:07 PM
gm now has complete assembled cnc ported LS3/L92 heads for $600 each, i picked up a set for my new LS3 and they do look nice

tennerv8
10-03-2008, 10:43 AM
Lets say I bought a set of bare L92's and wanted to go with the Ls3 valves you mentioned. What else would I need to buy to assemble these heads? Could I use the keepers from the stock Lq4 head that I will be removing?

whitew01ws6
10-03-2008, 12:13 PM
theres a guy on ebay that i have been seeing for a while now that always has these heads heres the linkhttp://cgi.ebay.com/ebaymotors/L92-L76-Assembled-heads-660-lift-Springs-LS2-LS7_W0QQitemZ230208594076QQihZ013QQcategoryZ33617Q QrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksidZp163 8Q2em118Q2el1247

1CAMWNDR
10-08-2008, 09:37 PM
gm now has complete assembled cnc ported LS3/L92 heads for $600 each, i picked up a set for my new LS3 and they do look nice

I saw your pics in another thread, does anyone have unassembled pics of the ports/chambers? Are there any flow numbers?

jay_lt4
10-09-2008, 10:49 AM
here are the flow numbers for the gm cnc ported LS3/L92 heads:

4" bore:
.100" .200" .300" .400" .500" .600" .700"
I..68...150...217...259...295...329...324
E..55...105...136...162...182...195...202

4.030" bore:
.100" .200" .300" .400" .500" .600" .700"
I..69...152...217...259...296...328...325
E..51...102...134...164...185...197...205

4.155" bore:
.100" .200" .300" .400" .500" .600" .700"
I..69...154...222...266...309...345...358
E..46...100...136...166...189...202...209

sixt9er
10-11-2008, 09:04 PM
I want to get a set of L92's for a future build. I want to run a larger lift cam (closer to 600 lift). Is it cheaper to buy the heads bare for $200 each and then buy the valves and related parts and higher lift valve springs? Or do I buy the complete L92's for $400 each and then just buy higher lift valve springs? This is a low buck build so if I could save a few bucks that would be sweet. Thanks fellas.

There is a little more involvement with these heads. I was a rookie with the L92 swap when I started. Mine were purchased bare for $175/each. I upgraded to Manley SS valves, had to purchase a set of L92 specific rocker arms, rocker arm stands, studs, a set of .650 max lift springs, retainers, locks, etc. It was beneficial to me to go the "bare" route and then build to suit my needs. It sucks because when I started this endeavor, no one was selling them in the configuration that I needed. Now you can mail-order a set of heads EXACTLY like what I had to piece together. :bang:

salemetro
10-12-2008, 03:43 PM
Just to echo what some have said here before....you get what you pay for. I just received my bare castings, and have Ferrea hollow-stem intakes and 6000 series exhaust valves on the way. It was a TOUGH decision, trying to balance cost against reliability. I initially thought that I'd be happy with 550hp N/A.....but for a semi-every-day driver, the car would not be as well mannered as I want....and it would be pushing the stock bottom end to it's limit. Sure, a "lopey" cam sounds cool...turns heads, etc....but how much FUN is it to drive on a long-distance trip?? I have since opted to turbo the engine. Once I got into it, the valves only cost right at 500.00 shipped. But of course, now I have to upgrade the rest of the bottom end. So, obviously, it depends on how fast you want to go....and how long you want it to last. I can tell you that I'm spending a $%&!load more now than I thought I initially would (oliver rods, Diamond pistons, Callies stroker crank)....but I know that it should live quite a while.

If you are truly doing this for a "future build"...then piece it together a little at a time with the best parts that you can find for the desired end-result of the build. Obviously, if you never plan to go FI or N2O, then that means the price of your build...and the quality of components required...goes down along with the target power output.

So, the old saying that "Speed costs. How fast do you want to spend??" definitely applies here.

Just my $.02

tennerv8
10-15-2008, 01:18 AM
Just to echo what some have said here before....you get what you pay for. I just received my bare castings, and have Ferrea hollow-stem intakes and 6000 series exhaust valves on the way. It was a TOUGH decision, trying to balance cost against reliability. I initially thought that I'd be happy with 550hp N/A.....but for a semi-every-day driver, the car would not be as well mannered as I want....and it would be pushing the stock bottom end to it's limit. Sure, a "lopey" cam sounds cool...turns heads, etc....but how much FUN is it to drive on a long-distance trip?? I have since opted to turbo the engine. Once I got into it, the valves only cost right at 500.00 shipped. But of course, now I have to upgrade the rest of the bottom end. So, obviously, it depends on how fast you want to go....and how long you want it to last. I can tell you that I'm spending a $%&!load more now than I thought I initially would (oliver rods, Diamond pistons, Callies stroker crank)....but I know that it should live quite a while.

If you are truly doing this for a "future build"...then piece it together a little at a time with the best parts that you can find for the desired end-result of the build. Obviously, if you never plan to go FI or N2O, then that means the price of your build...and the quality of components required...goes down along with the target power output.

So, the old saying that "Speed costs. How fast do you want to spend??" definitely applies here.

Just my $.02

Isnt there people on here running close to 1000rwhp with stock 6.0liter lower ends? I hear the cranks are strong at least.

Jason 98 TA
10-19-2008, 06:58 PM
We're about to run a special on out of the box L92 heads with PRC spring kit & milling! Checkout the sponsor section late this week & we'll have it up! The L92 stock valve is considerably better than most the aftermarket valves in terms of p/v. That is something to consider for you guys looking to install without valve reliefs.

That being said you might also consider the PRC cnc ported 6.2l heads. For the money they're really hard to beat gained over 20rwhp over a out of the box 6.2l head!!

Fb0dy0nly
10-22-2008, 08:46 PM
Isnt there people on here running close to 1000rwhp with stock 6.0liter lower ends? I hear the cranks are strong at least.

yeah stock cranks are good for roughly 8-900rwhp+. Good to upgrade rods, pistons, etc. tho.

Jason 98 TA
10-23-2008, 12:08 PM
I've personally made well over 900hp with a stock crank!!

Bcar
10-28-2008, 08:47 PM
Are the L92 heads ready to assemble when you get them bare from GM?