fastvet

iTrader: (2)

Let me pick ur brain. My question pertains to Runner size. I read everywhere that regardless of how good the Flow numbers are on the LS3 P&P heads, they cant compete against AFR's and Trick Flows performance (LS1 and LS2). So, within reason, the smaller the runner = higher velocity = faster acceleration = more power, right? If that is the general rule of thumb, what about this theory: Lets say a Drag car setup. 2 cars with exactly the same setup only difference would be the heads. Would something with the LS3 heads on a 408 with a 4.56 gear on a 32" tire out perform (or equal the power) to a AFR or Trick Flow head with the exact same setup at the track? Because lets face it, people like dyno numbers but the results at the track are what count. This question came up because I read that the AFR's and Trick Flow accelerate the motor faster due to the high velocity, so with this setup would they top out, or red line, before the end of the 1/4 mile if the vehicle was tuned with the LS3 heads for the track?

Different stuff I had thought about before this was: AFR/TF heads faster acceleration ='s gears ranging from 3.73 to 4.10 on a 26 - 28 inch tire. So can the LS3 head make up for this power using a lower gear ratio to ramp up the RPM's?

Its been on my mind for the fact that the LS3 heads are a budget head and if there was anyway of offsetting the power difference, I would like to go that route. I have a 410c.i SB LSx and still deciding wht route to go with on the heads. Any help will be appreciated and yes this will be for a strictly drag car. Thanks in advance for any imput!

Tainted

iTrader: (9)

velocity is a very important factor indeed,

however what a lot of people arent grasping about ls3 heads is valve shrouding. The heads flow great, but without a big 4.060+ bore to unshroud the large intake valve its not so great. on paper it may be, but as Pat G says, on a real running engine the cylinder filling is impaired by the shrouding.

if you arent running an ls3 bore OR LARGER I would stay cathedral style. Theres a thread in the dyno section "switched from ported ls3 to trickflow 235" and he gained HUGE power all the way across the board, especially in the low to mid lift range where that big *** lazy port of the ls3 isnt so great.

hope this helped

fastvet

iTrader: (2)

Thanks for replying. I'm on the fence here. My 6.0 is bored to a 4.04 with a 4" stroke making it a 410 or so. I like the TEA heads, which is what I am looking at. I just don't know if I can spend $2600+ on tf heads and not feel guilty about it being the right head. That's why I had brought up that theory about lower gears making it a faster rev. If anyone has opinions on what heads to go with, less than 2k, that will give me power like the TEA heads, please pm me or post here. Here's the setup: big cam (hopefully by pat g), 102tb/intake, sd tune, anywhere from 200-300 shot nitrous, and a power glide. I am looking to make just over 500 to the wheels, if not more, all motor and the rest with spray. Again, looking for hi flowing heads with good velocity under 2k.

silverz28camaro

iTrader: (20)

I agree with this...cathedral ports just seem to fit the 4.00-4.04in bore better. LS3 heads are NICE indeed, I would definitely go with those heads on a 418+ cu.in. motor or even on a 454 lsx build

Tainted

iTrader: (9)

heres a great budget head worth a very hard look.

Trick Flow As-Cast 220cc heads

Better than a gm casting, quality head with good flow, and can be ported later to be the full 225 through 245cc heads and anything else.

Oh, and they are $1650 brand new. Great ****** deal with lots of room for potential in the future and not feeling guilty about blowing $2000 but still getting a GREAT head.

fastvet

iTrader: (2)

Sometimes the things you read alot about are the things you first forget. I completely forgot about the as cast heads fro TF. Thanks, thats something to look into now.

Sales2@Texas-speed

iTrader: (5)

Check out the PRC LS3 250cc aftermarket casting heads! You still get the BIG flow but through a runner about 12cc smaller than the stock LS3/L92 runners (big air through a smaller port = velocity as mentioned above)! They work great on the 4.0x" bore engines, and offer as small as a 62-63cc chamber volume while still keeping BETTER valve drop than a stock GM LS3 head has.

http://www.texas-speed.com/p-3200-pr...der-heads.aspx

fastvet

iTrader: (2)

Thanks Matt. PM going ur way

WKMCD

iTrader: (2)

I'm really surprised no one has asked "what intake will you be running?"

3timeracin

iTrader: (15)

I don't think there is a clear cut answer to the debate on Cathedral vs. LS3 style heads. It all depends on your application and the complete package...I think velocity is important but if you have a 245cc cathedral head and a 250cc LS3 head, that 5cc is not gonna make a drastic difference in performance. You really need to look at the cross section that has a bigger impact than actual CC does.
another thing to consider is camshaft design for the LS3 style heads is finally coming around, take WKMCD 's motor for example. Relatively small cam and I would bet to say it makes as much power under the curve as any cathedral head would on that size engine. All because the complete package is right.

WKMCD

iTrader: (2)

Thanks, sometimes I feel like I'm preaching to the choir.

fastvet

iTrader: (2)

Intake is fast 102. Should be on the third post here.

fastvet

iTrader: (2)

What size cam u running? Sorry I'm doing this through my phone and its hard for me to mess with this to look up ur thread. What setup?

Tainted

iTrader: (9)

This is a good question as im going tgrough the same decision right now on a 408. Maybe Tony Mamo, Pat G, orr Brian tooley etc will chime in.

Id really like to hear their thoughts on the aftermarket ls3 style heads for small bore motors. Are the cathedrals still a better choice for the overall package. I know ots been argued both ways forever now but id like to hear some fresh up to date results from knowledgable minds that can explain the facts.

WKMCD

iTrader: (2)

234-242 but the lobes you won't find in a catalog...I couldn't.

Gray86hatch

iTrader: (83)

Going fast has less to do with the heads you put on the engine. It is the rest of the car that makes the car fast.

the greatest engine won't look good in a car that dosn't work or have the right converter.

Getting the rest of the combo is far more important than a cath or rec port head.

Lots of stock short block ls3 cars make really good power.

Tim

Jenson

iTrader: (32)

I'm currently trying to decide between cathedral or square port too. Although I feel like the small bore LS7 head trump all LS3 design's. I'm looking at AFR 230's, PRC 247's, PRC 265's, and one cheap option as AI's 243 race. LS3 heads would be my last choice.

Jimbo1367

That it exactly. People toss around brand, duration, lift & LSA but rarely tell in.ex lobes used.

fastvet

iTrader: (2)

I understand what you are saying. The thing is I want to do this build right. And right now I am on the part where I can get the best head (or best reasonably priced head) for a drag setup. Just don't want to spend twice like I did on the vette. Lol. I kno this topic has been beat to death, but I kinda wish some sponsors or shops to chime in here and help out.

fastvet

iTrader: (2)

How would these heads rank with ur knowledge on exhaust flow.

http://www.totalengineairflow.com/pr...s2ls6-stage-2/

They are a good bang for the buck, but what about for a 410ci setup with of course the fast 102