Quickin

Thinking of getting these instead of dealing with the LS7 head hassle that it seem like its going to be.

What gains did you see on what size engine?

Thank ya.

Beast96Z

iTrader: (21)

I don't believe anyone has them on a running engine yet. I know a few guys may have a couple of sets, but I haven't heard of any one getting them on their car as of yet. I ordered mine about a month ago for my large cube motor. Hopefully they will be ready soon.

Quickin

They're supposed to flow more than the LS7 heads (380cfm) with smaller ports, right?

BTL FED

iTrader: (9)

I just got mine yesterday, they wont be on a car for a little while (Alot of work left). But all I can say is they are a work of art, the attention to detail is amazing. I have seen alot of ls1 heads, AFR's, All-Pro's, and stock heads ported by about every shop around, and IMHO I have not seen a head that is even in the same league as these.

I will get some pics as soon as I can but here are the specs of my heads:
265 CC Race Heads
11 Degree Valve Angles
74 cc Chambers
Copper Valve Seats
Titanium 2.150 Intake Valve
Lightweight High Temp 1.60 Exhaust Valve
PSI .800 Lift Solid Roller Springs (These things look like they belong on a Big Block, they are HUGE)

The port work is Just amazing, and they are HEAVY, each head weighed around 39 heads, I have never seen a deck as thick as these.

Beast96Z

iTrader: (21)

There supposed to be the baddest thing to hit the market. Even better than theirs and GM's LS-7 head. The key factor will be the intake. The ET LS-7's with the LS-7 intake may perform better than the 265/FAST combo until ET's new intake manifold comes out next year. Of course this is only speculation because we haven't had any real world testing of the LS-7 intake put out yet. I'm just gunna use my FAST intake until the ET intake is avalible, then swap over. My heads were set-up for street/strip duty with the normal valve seats, stainless 2.125/1.57 valves, .700" hydraulic roller springs and titanium spring hardware.

Quickin

Are you going to flow check your heads on a bench?

Did you do more hand porting or are they already maxed out?


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Quickin

I'm not using the FAST or the LS7 intake

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xfactor_pitbulls

iTrader: (16)

Whats up with the 1.57" exhaust valve and 2.125" intake? Thats alot of intake for a small exhaust. Why not upgrade the exhaust seat and run a 1.64"? A 1.57" exhuast valve would have a hard time filling a big bore 1 7/8" header. I would have to assume that you are running 4.100" or bigger bore size, correct?

Brandon

Quickin

Whats the optimal intake/exhaust sizes for a 436ci with a 4.100 bore with a 250/252 113 lsa cam?

Beast96Z

iTrader: (21)

When I was talking to Craig about it, he mentioned valve spacing many times. He said when you start to get into such a large intake valve, it starts to get close to the exaust valve. Obviouslly the bigger you go on either side, the closer they get together. You want to keep a safe clearence between the 2, so I think that is why he wanted me to go with the 1.57". I sent him another message to see if he could at least get me a 1.60" in there without trouble. Obviouslly he can if BTLFD is using a 2.150/1.60. The bore on my motor will be 4.150+, so I want all I can get in there and still keep a good balance between intake and exaust. I deffinatlly don't want one hindering another.

Cary@Perf-Induction

iTrader: (1)

optional valve sizes are 2.100 or 2.125 intake, 1.570 or 1.600 exhaust.

the valve seat size will accept any of these valve sizes. a 1.570 exhaust valve on our 265 will flow 276 cfm with a 1 7/8 pipe. the 1.600 was a couple numbers better. The larger iintake valve won the coin toss due to having atmospheric pressure to deal with.


As far as valve ratio goes. look at the GM LS7 2.200 intake 1.615 exh.???

Quickin

What are you saying, I should go with the new LS7 head over your 265 head?

GPowrie

he is saying look at the ratio between the 2 valve sizes.

xfactor_pitbulls

iTrader: (16)

If it were me, I would have opted for atleast a 1.61 for that much A/F intake. Especially if the user is spraying. My point was that the 1.57" valve doesnt filled a 1 7/8" header as well as a 1.61+. You can get the throat of the seat out to the reaches of the exhaust runner more effciently with the larger valve. After all, dont think that an engine pulls the same as a flow bench at 28" of water. Thats something people never account for. Nonetheless, I cant knock the ET guys, ya'll are the pros and make a great piece. I am just curious what kinda power they make, N/A and spray. Cary, just wondering about one thing though. For the race only heads, why wouldnt you make a semi splayed offset valve angle to accomodate for the same rocker spacing and alittle room in the combustion chamber? Obviously it would cause to much wear for lots of miles on the street, but would be fine for track use. For the matter, they are your castings and you have to use the custom rocker setup, why not just give them some more room? With the big 4.1"+ bore sizes, there is alittle room to grow. Or is that the reason that you have to use the mohawk or jesel rockers for the bid CC heads?

Brandon

Beast96Z

iTrader: (21)

Cary, I pm'd Craig, but I'll let you know to. Will you make sure that my heads get the larger exaust valve? PM me if you need to.

Quickin

So how do you know which is best for which engine?

Different cams?

Spray?

Is there no one swize intake/exhaust ports that are good for them all? I'm getting better heads and a kick *** intake, an upgraded cam and a direct port. My bore is 4.100. So, how do I know what to get in the 265 heads?

Beast96Z

iTrader: (21)

You want to keep things proportional. A 1.57 exaust valve comes standard in alot of "smaller" heads. Most of those carry a 2.02, 2.05, or a 2.08 intake valve. When you up the intake valve to 2.100 or 2.125 in this case, you want to make sure the exaust valve moves up with it. It's not gunna do you alot of good to be able to inhale a huge amount of intake charge if you exaust valve can't move the air. A 4.100 bore could easily utilize a 1.60 exaust valve and it would keep a better "balance" between intake and exaust. All of ET's flow charts on the site use a 1.57 valve and they deffinatlly move some air, but on the larger bore motors, I believe a 1.60 would be more efficent in expelling exaust gases. And to answer your question, every set-up is diffrent. so one size fits all dosen't really apply. The larger the bore gets, the more unshrouded you valves are. This allows you to run more valve more efficiently. I wouldn't use the same valves on a 4" bore that I would use on a 4.100 or a 4.155. If the valves aren't shrouded by the bore, you might as well take advantage of it.

Quickin

I didn't mean "one size fits all the different types of engines". I mean, I have a 436ci. I want it to have good N/A power, but I'm also putting a direct port shot on it and I want to make sure the heads are set up properly for the 250 shot too. So, what will be the best if I get the 265 heads, for my engine and what I want to use it for? Which is daily driver N/A, and the spray from time to time from a roll. Never at the track. Just a street car. The cam will be something like a 250/252 113 lsa.

Thanks for the lessons.


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Beast96Z

iTrader: (21)

With the larger bore and the spray, you'll want the 2.125/1.60 set-up.

Cary@Perf-Induction

iTrader: (1)

Guys, before everybody gets cought up is a three page discussion over this, I would like to clarify this. I have been down in texas for the last four days running a whole bunch of different combinations with all of our different cylinder heads. I am learning as you guys are asking.

When we choose our exhaust valve size it wull usually have to do with the bore size/shrouding or our intake valve combo. We have different heads with different guide centers for different bore sizes. on our 215's, we use a 1.570 because they will usually be on a 3.9 bore and will be on a smaller engine. the radial distance on the exhaust needs to be at a minimum of .080 the have proportional airflow around the valve.


We like to use a larger exhaust valve on the 4.0 bore engines. Which we do even though we have not updated that on our website yet. The only exception is on a turbo engine we will desire the smaller exhaust valve for various reasons.