School us on engines...

I think you will get some more responses if you ask for some more specific information. You can write books on the differences and pros/cons between all those motors.

i am the one or some of this. let me sum it all up in one 5 word sentence.


Our's is cool, theirs suck.

how is that?


apples to apples.

my 5.4 3v against a 5.3 chevy LS-2.

stock

i make 300hp the chevy makes 303hp.

i make 365 tq the chevy makes 325tq.

the chevy's heads flow similar numbers to mine stock.

the chevy 5.3 weighs ~450-500lbs mine weighs 750lbs dressed

they both respond nearly identical to mods. as the heads flow great numbers at low lift.

i have aussie boss 280 intake for 4v , the chevy has an LS-7 available.

i have 4v 300cfm FORD GT heads available , the chevy has AFR 300cfm heads.

so, in the end they are equal.

all mod blocks bolt up all mod heads. intakes are not interchangable between head designs.

all mods use the same method for oil pump. with different pumps for each application.

2v is ok, 3v is better , 96 4v is great, 99-01 4v is fantastic, 03-04 4v is titanic , FORD GT is king of all.

2v ported head flow ~220200cfm, ported 3v flows 282/207 cfm, ported 03 flows 315/240 cfm, ported GT flows >330/250 cfm.

intakes 91-95 sucks, 86-98 sucks less, 99-04 is fair,93-97 intech4v works, 96-98 cobra works better,00 cobra "R" is good, aussie 4V is best.

exhaust: 91-04 2v sucks, 91-97 intech 4v sucks, 96-98 cobra sucks, 05-07 mustang gt is good, 5.4 3v is good. none are great

blocks are deep skirt crossbolted mains. 91-98 TEKSID are the best imo. 91-04 gt blocks are ok. most blocks can handle 700hp. come 5.4 can handle 1400+ hp. NVH blocks can handle 1250hp.


that's all i know and some of it may be wrong. feel free to correct me.

the lt-1 has crappy heads but cubes keep them in it. ls-1 makes reasonable power but it again all cubes. ls-2,6,7 use cubes.

now the hemi, that's a different story.

their heads are better then most all stock. they flow 260 cfm. good intakes, etc. too long to write.

maybe you should invest in some books on Modular Engines...Sean Hyland has a decent one to start with....
Also Google...

that's a capitol idea. there's just too much.

Billfisher is the man when it comes to these motors. I hang on his every word like its going out of style.

Bill how hard is it to get the Aussie 4v setup?

well most of teh motors mentioned where designed to perform at certain ranges but can be modified to work at a different range like it being a TQ motor or HP motor. But it can all be determined by head desing (including valves and ports, plug location and everything involved), intake, carb/EFI system, exhaust, compression, and then all the internals in the block......

So if you are looking for what motor has or had the best capabilty for its time or just an overall best motor

I think Bill was referring to the 5.3 V8 in the Impala SS that is 303hp not a 6.0

DropTopPony said:

I think Bill was referring to the 5.3 V8 in the Impala SS that is 303hp not a 6.0

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He said LS2...the 5.3L in the Impala is not a LS2.

LaserRed01GT said:

He said LS2...the 5.3L in the Impala is not a LS2.

Click to expand...

he also said 5.3 303 HP so he meant the other engine...some people make mistakes while typing...

DropTopPony said:

he also said 5.3 303 HP so he meant the other engine...some people make mistakes while typing...

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I think he meant LS2 and was purposely using the lower HP of the 5.3L to his argumentative advantage. But, that's just my opinion. He'll probably just say he was comparing similar displacements. Well you can't compare a purposely performance built 5.4 to the GM 5.3 in the Impala which was not designed for performance yet to power a platform that was on par with a midsize sedan.

Billfisher seems to have developed a noticable pattern, it goes a little something like this.....Bill's 5.4L is the best motor in the world and everything else sucks.

MERRY CHRISTMAS!

a bone stock ls-2 flow nowhere near 270 cfm. you are dreaming. even ported ls-2 heads advertised at 300 cfm flow only 270. you are believeing bull crap.

goto web.camaross.com. you have to know the enemy to beat them.

they are the gurus for LS and they say it's a lie. the only real 300 cfm head is the 225 AFR. apparently you are not a guru.

that unbeatable stuff is just hype. they tested those CNC heads and they fall short. like i said they flow no more than a stock set of 99+ 4v. maybe even a little less casting to casting.

the 5.3l chevy is an Ls-2 like clone. it is actually a better head than the LS-2. i know the specs on stupid chevy's.

if the ls 5.3 was so killer and had 270 cfm there's no way it only makes 303. the fact is, it flows no more than my heads and makes way less torque.


what has happened here is the 2v modular has poisoned your minds into thinking a certain head flow or port CC's cannot support power in large cubigc inch motors.

for example. a 1.88" intake valve in a 162 cc port can flow how much? now i'm talking NHRA spec motor.... 270 cfm. and how much power is that? 470+ out of a 360 cuin motor.

it doesn't take 300 cfm to make power, especially if the velocity is too high or too low. either direction will kill you. my 4v heads ported to flow 300 cfm and 230 cc's will hurt torque even in my 5.4. but fr-500 175 cc ports flowing 270 cfm make 500+ easily. so....

those flow numbers you are dreaming about don't exist. now hemi's do in fact have the most advanced ports 2v. the best money can buy, and they require little lift to get 260 cfm factory. you want to know what every LS boy fears.... 6.1l hemi in a light cat. say an "A" body lightweight with 425hp and good economy. good luck beating that.


ask yourselves why a 5.3 LS has so little power. forget the excuses. it doesn't have the cubes to make 400hp factory.

if i don't get everything right, i'm ok with that. again feel free to correct me. i am wrong all of the time. but chevy's still suck, and the make little power per cube.

the 6.2l boss will set it all right. hopefully.

i used the stock truck number to compare the LS 5.3.


not these.
my motor is not the greatest, it sucks also. but not forever. im' trying to encourage you guys to stop complaining and do something all-motor that gets respect of the enemy. they laugh at supercharging. they add n2O and get back on top. beat them all-motor.

mine 310hp, 410 lb-ft
5.3 LS 303, 325lb-ft.

i win. my motor is not really modded. without a custom tune it stops making power at 4200. so tp call mine modded like it's an all-effort motor is kinda lame.
pullies,t-stadt,cmc delete, 'x' pipe. wow 15hp. with cams 9 degrees advanced, that's quite a handicap for me. take away 25 hp from stock. i am really anti-modded. sheesh.

chevy sucks. too many hype it.

Take a minute to walk a mile in my shoes you might understand why myself and all the other competent and experienced engine builders are leary about just about 98% of the junk posted on automotive oriented forums. I will include some factual information below from my shop and a few others regarding LS2 cylinder head flow data. I have spent over 150-200 HRS on doing LS2 cylinder head flow analysis alone. Most shops invest about 50-100 hours developing a particular head flow model and program.

Everybody knows that larger volume ports can lend themselves to allowing for bigger flow numbers....actually getting good flow numbers is another story....especially in a "production" environment. A good portion of the cylinder head shops out there just don't have the machinery and toolage nor competence to properly port and work a cylinder head to achieve a maximum effort head. On the flip side, any truly competent cylinder head shop can absolutely produce solid results on a pair of heads they invested hours and hours into.

Take this below info for what it's worth. Believe it, don't believe it, throw it in the garbage, call it BS, or you could have have an open mind and learn something that just might help you down the road.

The below SF-1020 flow workup represents a set of LS2 heads we sent off last summer when we got a test 2005 GTO. These were bone stock off the car heads. I hadn't received my SF-600 yet. Keep in mind these were flowed on a Super Flow 1020 and these are known in the cylinder head business as being a bit "stingy":

View attachment 414863

The below is a set of LS2 heads we did earlier this summer. These were done on our new SF-600. They have been Stage 3 ported with 2.02/1.60 4 angle valves. The rocker boss and valve guide boss were left untouched...in other words a street head.

View attachment 414865

I work with and talk to several different cylinder head shops all over the nation on a regular basis and they all consistently obtain very similar results on their LS2 castings. The L92 truck heads (PN 12582713) and LS7 heads have shown to flow well over 60-80 CFM more than the fully ported LS2 castings.

i can only base my information on reading others findings. you observations are duly noted and filed.


chevy still sucks.

better info than posting flow number is a velicity chardt that show actual flow through the lift cycle. if those port are that good there should be no drop off in filling at or near max lift. in other words there will be no dead spot in the lift cycle of the port. it is useless to lift to .600 if the velocity and filling drops at .580. the net loss of filling negates a meaningless flowbench number. i haven't seen a chart that shows that, but i am curious what the actual usefulness of these huge ports is.

a 96 cobra port starts at 222 cc's. it can be ported to even larger cc's and be made to flow ludicrous numbers. but in the lift cycle of an actual cam, filling stops increasing long before max lift is obtained, thereby making any higher lift useless.

that's my real concern with these street heads lifting to .700 and quoting those numbers as actual usefull street hp and torque.


i do however agree that the ls7 and new truck heads are out there on power. for mr the jury is out on ls1,ls2 as being that good. your opinion is countered by other chevy experts opinions. one thing this conversation has managed to accomplish is to reopen my 4v consideration.

billfisher said:

better info than posting flow number is a velicity chardt that show actual flow through the lift cycle. if those port are that good there should be no drop off in filling at or near max lift. in other words there will be no dead spot in the lift cycle of the port. it is useless to lift to .600 if the velocity and filling drops at .580. the net loss of filling negates a meaningless flowbench number. i haven't seen a chart that shows that, but i am curious what the actual usefulness of these huge ports is.

a 96 cobra port starts at 222 cc's. it can be ported to even larger cc's and be made to flow ludicrous numbers. but in the lift cycle of an actual cam, filling stops increasing long before max lift is obtained, thereby making any higher lift useless.

that's my real concern with these street heads lifting to .700 and quoting those numbers as actual usefull street hp and torque.


i do however agree that the ls7 and new truck heads are out there on power. for mr the jury is out on ls1,ls2 as being that good. your opinion is countered by other chevy experts opinions. one thing this conversation has managed to accomplish is to reopen my 4v consideration.

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I was impressed at first that you displayed maturity and were willing to admit that your input on this subject was your simply your opinion (billfisher -“i can only base my information on reading others findings”) and that you did not have any discernable experience on the subject of cylinder head development. Then, you couldn’t leave well enough alone, and your desire for an attempt at self-admiration took over and led you to make your last post in a desperate attempt to impress your piers here. And of course, you again, felt the need to end your post with an arbitrarily negative and unnecessary comment towards Chevy (GM).

I am going to delve deep into my psychic abilities and go out on a limb here that you probably spent most of the day yesterday scouring the internet searching for some sort of relevant information that you could copy and paste, then fumble over and change up the wording (and proper spelling) that might give you the opportunity to make a last ditch effort to sound as if you actually had experience with cylinder head design and development.

I was again impressed by your last post…..that is….until I got about 9 words into it when I read stuff like this: “velicity chart”, “useless to lift to .600 if velocity and filling drop off at .580”, and “the net loss of filling negates a meaningless flow bench number.”

Mr. billfisher, allow me to share with you the reality of cylinder head D&D. Perhaps you should listen closely, because it sounds like you need it.

Before any flow testing can be performed, the flow bench must be calibrated for that day's air conditions. Then you set the cylinder head on top of a bore fixture with the appropriate bore for the particular application. A dial indicator is then placed on the valve. We then use a threaded actuator to push open and hold the valve at the target lift being tested. Some people will use lighter rate valve springs in order to make the valve actuation easier, but the lighter springs, specifically the opposing spring from the one being tested, can be sucked open and skew the results. This is more common than you can imagine. I use the actual spring that will be used in the application. Once you record and “sync” the flow data, then you can plug the lift/flow data into FlowCom and/or a data analysis program. V = 1096.7*Sqrt(H/d). Once velocity has been calculated, the volume can be calculated by multiplying the velocity by the orifice area times its flow coefficient.

A cylinder head with a relatively small intake runner and high velocity characteristic can be a good or bad thing. Contrary to the popularly perpetuated internet myth, if you work a cylinder head so that it shows an exceptionally high velocity profile which results in sacrificing even moderate amounts of low lift and mid lift airflow (CFM), you'll lose power. Even if it shows gains at the upper lift range. That’s just the nature of the beast. Conversely, high flow (CFM) capability is very important at upper and peak valve lift, but not at the expense of the low lift velocity that initially gets the intake charge moving and keeps it moving even as the valve closes. Increased velocity or flow will not necessarily get you more charge after IVC if the motor is not tuned for that specific point in RPM, but with some careful intake runner pulse tuning we can optimize the velocity/flow to IVC relationship. The speed at which flow begins as the valve begins to lift is critically important. That speed creates gas inertia that helps fill (or empty on overlap) the cylinder as thoroughly as possible. A thoroughly stuffed cylinder normally equates to power, but the proper runner volume for a given application that has a relatively small cross section and a relatively high flow, will produce good results on a street/strip motor. Maximum effort drag race heads are given a slightly different approach and will typically require a larger runner volume. For instance on the LS2, the stock 211cc intake runner’s cross section works well for a street/strip low cube (under 350”) motor, but for a high HP motor or a maximum effort drag race head, you can focus more or your time in the runner to increase it’s volume. This can be done by changing the geometry of the entire port….SSR (short side radius), ceiling radius, SSR apex, strategic removal of material, etc. The right combination of runner volume and flow will lend itself to increased port airspeed. This will help to eliminate fuel separation, reversion, promote swirl, and increase the air/fuel intake charge. All which equates to performance and power. There are little tricks to manipulating flow characteristics. You can partly control the lift to flow characteristics by way of valve grinding. A inner radius cut (back-cut) can lend itself to improve the effect on low lift and mid lift performance, whereas valves without a back-cut tend to accentuate the very high-lift numbers. It all boils down to the motor combination and its purpose.

In spite of the perceived limitations of a flow bench, in skilled hands it still provides an excellent source of information in order to guide the engine designer/builder in deciding how to go about modifying the head and other engine components. Head flow data is also essential to provide accurate port flow coefficient data that is required for the use of data analysis software. With that data analysis software and flow data teamed together, it provides a powerful way to finitely understand a running motor and it's unique characteristics. Details which are just about impossible to view any other way. A flow bench is a valuable tool if used for what it is that can help fine tune a combination, but obviously it is not the ultimate authority.

My opinion has been countered by other Chevy experts huh? I cordially invite them to come aboard in this thread and participate in a discussion of cylinder head technology.