Floorman279

iTrader: (11)

i purchased a motor from a member on here.....will be taking opinions from you guys on which direction to go and what parts to throw at this 427+ N/A build. this is for my 2000 camaro street car.....since this is a street car, we will be shooting for a strong 2500-4500 rpm range, and hopefully make a good amount of power up top, so id say the low mid range torque is 60% of my priorities, and high end is the other 40%.....id say id be wanting to peak around 67-6800 and shift around 71-7200. will not be ready to build until early next year, but would like to gather my parts list now in case some stuff shows up in the classifieds. once we decide the heads to go with, thats 75% of the battle, we can pretty effortlessly discuss weather to go LLSR, SLR, what rockers intake cam springs etc etc. but please id rather wait to talk about that stuff until after the head decision is made, so please refrain from the "run this head with this cam, you will make 625 rwhp and will pull like a ****"...will post pics later this week when it arrives.....


so thats the intro, lets talk about what i have.....got an ERL sleeved ls2 with ls3 heads from a member on here. it was connected to 2 turbos and made north of 1000rwhp......i will be getting it torn down, rebuilt, and everything checked including the callies rotating assembly. it currently is a 429, so it will get rehoned a little but not bored out. we will be shooting for as much compression as possible on 93 octane, so that means new pistons which we can discuss after the heads.

the heads which is my big dilemma, are very very nice TFS Gen X 255 ls3 heads. they have inconel exhaust valves, hand done bowl work, dual springs obviously, and titanium retainers.......found a few cars out there running these, and 6.2L ls3s have been making around 530-550 rwhp consistently with these heads.......very good numbers. But i can't really find these on a big bore motor.

i did a lot of research and couldn't ever really figure out why ls7 vettes can consistently break get 610-625 rwhp with a big cam and worked heads.....i also noticed that 418-427 ls3s usually get around 570-590 rwhp, and most of the time those are in solid axle cars which are supposed to eat less power than the IRS of a vette.....what gives, both 427s, but yet the ls3 cars are down 50 hp at the crank? so i did more research and found that bore size is more important than stroke....yes the ls3 stroker has a .100 larger stroker, but the ls7 has a bore that is .0625ish larger which seems to be the huge difference here.......reading up the larger bore allows larger valves and less shrouding etc.....im getting somewhere i promise

after learning about that bore size is key, my question is, should i consider running a head "MADE" for a 4.125+ bore instead of running the trick flows i have now that are designed for 4.00+ bores? not knowing a whole lot about this stuff, im thinking that id be leaving a little bit on the table by not running the "largest" head possible (not talking about port size)

for those unfamiliar, here is the info https://www.trickflow.com/parts/tfs-3261t001-c01

what i like about these heads:
1)12 degree valve angle so i could get forged flat tops
2)huge huge increase in exh flow, i believe its about 85 CFM more than stock ls3 heads
3)the hand work on the bowls is a plus, and the valves have also been lapped
4)$$$$$ they are free cause i already own them, but by the time i send them off to get checked, clean, new springs etc i will be in for another 400 or more if someone assembles them
5)the 255 ls3 port seems perfect for my goals.....a good free flowing size port that isn't goona give up the low end from being to big, but will flow very well up high (remember my 60% low end 40% high end goals)

what i dont like
1)wouldn't mind running larger ls7 valves, or larger if possible
2)the possibly of giving up power by not running a head made for larger bores

sorry for the novel, just wanted to explain my thought process.....build it right once. i know i will be told keep what you have for financial reasons, but if i say sold these and got 1800, then spent 800 on ls7 take offs, and got them ported and assmebled with goodies for 2000, id be in an extra 1000 bucks but depends on what gains i would have if it would be worth it.....im very much so leaning towards keeping what i have cause they seem like very good heads......thanks ls1tech. hope to hear from asthma, hammer, chevelle, and that other guy

Tuskyz28

This is a article you might find interesting.

https://www.powerperformancenews.com/tech/tfs-family-feud-cathedral-vs-ls7-head-test/

All guys on here go say something different honestly. Kinda me asking you what's your favorite luxury car? One guy go say Lexus.... next guy go say Range Rover.

Floorman279

iTrader: (11)

yea ive seen that one......the problem is the ls7 are known to be high end happy and at decent at best down low but from what i have seen without a ton of effort, the ls7 heads are nothing to write home about down low......i will look for some cathedral heads designed for 4.1 or bigger bores and see what i can come up with.....the ls3 heads however tend to be better down low from what ive seen than the ls7 heads and can be very decent up top.......so i should switch the topics to large bore cathedrals vs my current heads.

Floorman279

iTrader: (11)

that test isn't that great tho......msd intake on the fast fully taking advantage of the ls7 in the high end, and the fast lsxr (assuming long runners since nothing was mentioned) fully taking advantage of the low/mid range cathedrals are known for

G Atsma

There are no cathedral heads made for that large a bore. Cathedrals have the valves too close together to put larger valves in. This is why LS3 and LS7 heads have offset rockers on their intakes as the valves got moved to accommodate the larger valve diameter. Only rectangular port heads can have the larger valves.

01CamaroSSTx

iTrader: (3)

MAST Motorsports 275cc Cathedral Ports for 4.125 + Bore and equipped with 2.20 Intake valves

01CamaroSSTx

iTrader: (3)

They're proud of them as well they should be.

slogo

Well there are these. https://www.mastmotorsports.com/products/ls1-295

01CamaroSSTx

iTrader: (3)

And built to my wants would set me back just over 4G....

Floorman279

iTrader: (11)

guess there was a lot of R&D to get them to work.....4000 is too much lol

01CamaroSSTx

iTrader: (3)

Yah! But then again I have just over 3G tied up in my TSP PRC 265's

QwkTrip

iTrader: (23)

You've got some pretty nice heads already. You can spend gobs of money on a naturally-aspirated engine trying to get that last little bit. If you really want to take it to the next level then consider a power adder.

FWIW I am putting together an LS7 with Mamo 265 heads which are ported TFS 260 heads. That's a pretty awesome head for a daily fun car. Gotten kind of expensive though.

G Atsma

I believe I stand corrected..... Mast does it!

Floorman279

iTrader: (11)

one consistent thing im seeing is a lot of the big guys love to touch up any TFS heads. qwktrip, since this is a "how much power can i make on a decent budget" motor i really should stick with what i have.......does anyone know if using 4.00 or bigger head instead of a 4.125 or bigger head is goona be restricting a little bit?

G Atsma

I really doubt it. LS3 heads in OEM form are good for 600HP, more when ported. I looked to see what your HP target is, but didn't see it. It IS late so might have missed it. While they are likely better than LS7's for low end, they are WAY cheaper and might just be what you need. Those and an LS3 intake will go a long way to a lot of power, AND be easy on the budget.

big hammer

big hammer

Patron

Post ^ #15 is Correct. A 427 Factory Ls3 heads and intake will do* just both ported that I'd be willing to bet on. Uses a LLSR cam to fill the cylinders with around 236 - 242 of degrees @ .050 being that it's a solid roller would be in the realm of what your looking for here's a smaller combination with your Top end and a larger 427 ls3 combination with a HR cam. Add the solid roller of the smaller build with I'd say 2 - 6 degrees * (238-242) on the intake side with a 427 that's around 600+ rwhp *Manual trans if you've got the small stuff like Higher compression,Vacuum pump, elec. water pump, etc.....

Smaller Factory sized Ls3 with some head work and a LLSR....

https://ls1tech.com/forums/generatio...hp-484wtq.html

How many of you guys know or remember WKMCD? LMAO!!!!!!!!

Long read.....
https://ls1tech.com/forums/generatio...b-c-d-e-f.html
Short read...... I looked out 4 U....
https://ls1tech.com/forums/parts-cla...ale-cheap.html

Patron

Sorry to disappoint you but some combinations just add up(U can Learn alot from a dummy)...I can go on and on with Factory Ls3 head combinations you just want to make HP @ 6700-6800 peak. Fill the cylinders .650+lift, get the Compression up and your done just with a shorter duration cam of 236 to 244 duration on the intake side. Ask KIP or Speedtrigger with CamMotion. We just need roughly around 660 to 670 @ the crank to make 600rwhp with a manual trans. Your Done! Now how Hard is that with 427 cubic inches? Again Some combinations just add up.

Tuskyz28

Anybody have PROOF that a LS3 head is better down low vs the LS7?