Best bang for the buck cylinder head?

**Firebirdjones** · 02-22-2010, 12:44 PM

Originally Posted by mark21742

I'm still runningg my oringinal 241s ported and milled for now, but I'm saving and reading reading reading to make a good choice when the time comes to buy heads.

Understandable. I wouldn't have any problems putting the L92 heads on a 400 ci + motor.

On the other hand, there are some nice cathedral port heads on the market that flow enough to support well over 600 hp. They cost much more than out of the box L92's though. Depends on your goals.

**mark21742** · 02-22-2010, 02:35 PM

Originally Posted by Firebirdjones

Understandable. I wouldn't have any problems putting the L92 heads on a 400 ci + motor.

On the other hand, there are some nice cathedral port heads on the market that flow enough to support well over 600 hp. They cost much more than out of the box L92's though. Depends on your goals.

I have what I want for now in the bottom end, I won't be doing heads till atleast next year...unless I win the lotto lol

**robznob11** · 02-22-2010, 05:59 PM

I know you don't run l92 s on small engines they wont even work on less than 6.0 engines because the valves would hit. the point is that gm offers heads what ever casting you want that are upgraded from the factory you can get them at scoggin dicky performance probably cheaper than else where. just throwing a bone not everyone knows where to source a good deal its worth a call.

**jetaws6** · 02-22-2010, 07:55 PM

Jegs has good prices on ls6 heads

**garygnu65** · 02-23-2010, 05:15 AM

SDPC sells #12564824 for $445 each,ls6 head.

**Firebirdjones** · 02-23-2010, 05:48 AM

Originally Posted by robznob11

I know you don't run l92 s on small engines they wont even work on less than 6.0 engines because the valves would hit. the point is that gm offers heads what ever casting you want that are upgraded from the factory you can get them at scoggin dicky performance probably cheaper than else where. just throwing a bone not everyone knows where to source a good deal its worth a call.

Ya I think we all know you need a 4 inch bore for the L92's to work. What I was getting at is,,,,,although those heads are a good deal, they have way too much intake runner volume to work well on anything under 400 cubes. So even the 6.0 (364) with it's 4 inch bore wouldn't qualify in my book. GM high tech proved this as well with a very soft motor on the dyno that was peaky.

Now throw a power adder in the mix like a procharger or turbo and we have a completely different story. But a naturally asperated motor I would not use them on unless you are building a stroker.

Not to mention, they also have a very weak exhaust port. Even after CNC porting the IE ratio isn't that great. Those heads need a huge duration split of at least 10-15 degrees to compensate for the weak exhaust side.
I agree the price is attracting, but when I look at all other things considered, there are better options even if they cost a little more.

**NoscamaroSS** · 02-23-2010, 08:35 AM

^^^I am glad to finally find somebody who understands what im talking about in respect to the L92 head. Ive tried to explain the same concept to several people but they are all hung up on flow numbers.

**mark21742** · 02-23-2010, 09:09 AM

Originally Posted by NoscamaroSS

^^^I am glad to finally find somebody who understands what im talking about in respect to the L92 head. Ive tried to explain the same concept to several people but they are all hung up on flow numbers.

Using high velocity theory, with the big long ported runners of my Proflo xt port matched to my, ported/ milled 241s with their stock sized valves actually be helping me make power, or more of a restriction over bigger valve bigger heads?

**Firebirdjones** · 02-23-2010, 11:21 AM

Originally Posted by NoscamaroSS

^^^I am glad to finally find somebody who understands what im talking about in respect to the L92 head. Ive tried to explain the same concept to several people but they are all hung up on flow numbers.

Nothing any engine builder wouldn't understand. Problem is, people have gotten hung up on dyno numbers and and flow bench numbers. Neither of which means the car is going to be fast.

Peak flow isn't all it's cracked up to be. Even if you had a camshaft that reached peak flow (say .600") it only hits that one time during the cycle. What everyone should be more concerned about is mid lift flow, say .300"-.400" because you pass over that twice during the lift cycle.
AFR has been hard to beat in this area, Trickflow is another one. Prices reflect that.
L92's hit the market and it was all the craze because of the cheap prices. Ya they flow 320 cfm on the intake side, but mid lift numbers aren't impressive, and the exhaust side sucks.

Not to mention take this for example-------------------------------------

If you really look at it, and this is where people should pay close attention,,,,,,,,,,you are looking at heads with an intake runner size of 260cc,,,and it only flows 320cfm!!!!!
You can port cathedral heads with an intake runner size of 205-220cc and get 320 cfm of flow.
Now which head do you think is going to perform better accross the board??? I'll take the smaller cc intake runner any day of the week, smaller intake runner means more velocity, better throttle response, better torque with a nice smooth curve on the dyno graph that theoretically would still make the same peak HP, and more average HP accross the board.
And we aren't even taking into account the weak IE ratio of the L92's. That would be yet another factor.

I don't mean to dog the L92's, my hats off to GM for offering a new head so cheap. They work well on larger motors that need an intake of that size to fill the cylinders. Smaller cubes could be made to work, but expect peaky performance that would require alot of rear gear and high rpm shift points. And there is certainly nothing wrong with that, if you like that sort of thing.

**SOMbitch** · 02-23-2010, 11:34 AM

Originally Posted by mark21742

How about a 404 stroker with an Edelbrock proflo xt?

L92's with a well matched cam it would be wicked on that motor and the most economical way to 500+rwhp......

**NoscamaroSS** · 02-23-2010, 11:36 AM

Originally Posted by mark21742

Using high velocity theory, with the big long ported runners of my Proflo xt port matched to my, ported/ milled 241s with their stock sized valves actually be helping me make power, or more of a restriction over bigger valve bigger heads?

Firebirds post pretty much summed it up, but I believe you definately would benefit from having a little more runner volume and a larger valve size since you're running a large cube stroker.

**Firebirdjones** · 02-23-2010, 11:37 AM

Originally Posted by mark21742

Using high velocity theory, with the big long ported runners of my Proflo xt port matched to my, ported/ milled 241s with their stock sized valves actually be helping me make power, or more of a restriction over bigger valve bigger heads?

Hard question to answer. Who did the work on your 241's and what was done??
Keep in mind switching to L92's also means switching your intake setup completely, which adds to the cost.

Like others mentioned, it really comes down to cost and how much HP you are willing to sacrifice per dollar spent.

**Firebirdjones** · 02-23-2010, 11:39 AM

Originally Posted by NoscamaroSS

Firebirds post pretty much summed it up, but I believe you definately would benefit from having a little more runner volume and a larger valve size since you're running a large cube stroker.

Oh ya you are right, he did mention he was building a stroker didn't he???

**azfrc** · 02-24-2010, 07:10 AM

How did this discussion go to L92s? There's a whole section of the LS1tech forum dedicated to fourth gen small blocks and a lot of write ups on 6.0 liter/L92 intakes. They seem to get pretty good reviews.

Has anybody ever seen dart ls heads for $700 a pair? Where?

I'm disappointed at the flow resultsof the LS heads since I have run a set of Dart pro1 200ccs and been very pleased with the power on a 388. Of course that was a small block in a 240z weighing about 2500lbs so bottom end torque was not a priority.

**Firebirdjones** · 02-24-2010, 08:14 AM

Originally Posted by azfrc

How did this discussion go to L92s? There's a whole section of the LS1tech forum dedicated to fourth gen small blocks and a lot of write ups on 6.0 liter/L92 intakes. They seem to get pretty good reviews.

Has anybody ever seen dart ls heads for $700 a pair? Where?

I'm disappointed at the flow resultsof the LS heads since I have run a set of Dart pro1 200ccs and been very pleased with the power on a 388. Of course that was a small block in a 240z weighing about 2500lbs so bottom end torque was not a priority.

Thread has been about best bang for your buck heads, and naturally the L92's come into play. Wouldn't know much about LS1tech articles, I don't frequent over there at all.

Ya the Dart LS heads were in a recent article that was linked in a thread earlier here. May have been this one, I get them mixed up.
They talk about prices and how affordable they are. Wasn't a terrible head, but they were compared against AFR's and Trickflows.

I also run 200cc dart heads on a gen1 406 that made ~480 hp with a very mild 240 at .050 cam on pump gas. Great daily driver. They make a pretty decent head for the gen 1 engines. We only did a little clean up work and some bowl blending for the 2.05 intake valves we installed. Otherwise they are out of the box.

**azfrc** · 02-24-2010, 09:07 AM

Originally Posted by Firebirdjones

We only did a little clean up work and some bowl blending for the 2.05 intake valves we installed. Otherwise they are out of the box.

I like the power they made, but l had to clean mines up as well. I cut my hand on a pretty big casting flash.

**mark21742** · 02-24-2010, 11:28 AM

Originally Posted by azfrc

I like the power they made, but l had to clean mines up as well. I cut my hand on a pretty big casting flash.

The first thing I did to my heads was to around off every sharp edge so I wouldn't cut myself up...I should buy stock in the band aid companies lol

**ultra_z28** · 02-28-2010, 06:59 PM

so what would be the best heads/cam for a stock lq4 and it be a daily driver

**dbs1** · 03-03-2010, 04:12 PM

I'd have to second that on the L92 heads. I have a nbs 07 truck with the 6.0 max pkg that has the L92 heads. I previously had the 06 with the LQ9 6.0 engine. Both trucks ran a 15.2 with the L92 headed truck almost 3 mph faster, but a dog out of the hole. It starts to wake up after 4200 rpm, but the heads overwhelm it. It seems gears or a different cam or stroke it would help, but it won't win many stoplight wars.

I am curious what cnc'd 241's will do with a 224/228 588/588 cam and the accompanying bolt ons?

**Firebirdjones** · 03-04-2010, 08:10 AM

Originally Posted by dbs1

I am curious what cnc'd 241's will do with a 224/228 588/588 cam and the accompanying bolt ons?

Should be an 11 second 4th gen. I had a flow chart here somewhere that compared ported 241's to ported 243's.
The 243's had an exhaust flow advantage and therefore a better I/E ratio. But otherwise somewhat comparable in HP.

The better I/E ratio would favor a straight pattern camshaft. The split duration camshaft you listed might be better suited for the 241 heads that lack some of the exhaust flow of the 243's.