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I'll mention street car stuff 1st.
400-427ci (4.125" bore) say compression at 12.5:1 to 13.0CR I'd for sure run a 10*-12* LS7 castings to run a healthy cam shaft. Won't fell lazy from light to light as many may think.
370-416 (4.000-4.070" Bore) I'd stay with an LS3 Rec port so many great options from stock to aftermarket 10* heads which are our most popular head our road course guys run with 376-416 mid bore stuff.
Small bore of course a 243 with bigger valves with some nice compression.
This is what I've and would run on my personal NA mild builds for a car I'd drive for long periods of time (Not daily, cause ranch).
Power adder stuff can vary depending on what power adder street strip or class/competitive racing, blessed to have a hand full of customers in all fields
So with the light to light and under the curve power with an LS7 casting what intake would you use with this setup JR?
Would you say a camshaft in mid 240's range for a 427?
The only intake I can think of that will fit under the hood is either a FAST 102 or an MSD.
Does the flatter 10* valve angle work better than the stock 12*?
Oh no, what happen to our boy Smokey_B? I like that guy.
Let's just say there were a few issues going on with some of his postings and I guess LS1 tech decided to ban him.
He did have some good information when he wasn't having a rambling moment.
He did PM me a few times to give me advice too.
This is NOT an attack on MAST as they are great friends of ours but wanted to show why our F310 LS3 castings have been our most popular head. From 4.030" to 4.185" Bore.
Our magic starts with our valve center line being moved, spark plug location and angle moved still an inline casting. intake runner raised to efficiently fill the cylinders without sacrificing low and mid range performance. Exhaust ports raised .200 and it shares LS7 rockers with a corrected valve-train geometry vs a OEM style LS7. Our F-Series are a different animal but this is a nice example what an nicer LS3 can do as well depending what your build may be and rpm range you are targeting. Cam used 246/256 113+3 427ci 10.5:1cr mule motor. This combo gets turned at 8k rpms with 91oct
JRFed~ Smokey is over on yellowbullet holding it down. I speak with him twice a week at least.
On the other note... I've mention on here ch countless times that Frankenstein has the meanest LS3 head program I've ever seen period. I go to the LS fest yearly and I see what runs hard and what actually does/doesn't works.
That LS3 head you guys have looks mean.
And that's with a reworked stock casting?
Are those dyno figures on an engine dyno?
Thank you sir, they are our own in-house castings. Check this pics out and look at the raised intake and exhaust ports. how much we moved the valve geometry and spark plug location and angle. Notice the centered exhaust ports to the valves vs the off set OEM one. This was on a engine dyno with 91oct
JRFed~ Smokey is over on yellowbullet holding it down. I speak with him twice a week at least.
On the other note... I've mention on here ch countless times that Frankenstein has the meanest LS3 head program I've ever seen period. I go to the LS fest yearly and I see what runs hard and what actually does/doesn't works.
Thank you sir, they are our own in-house castings. Check this pics out and look at the raised intake and exhaust ports. how much we moved the valve geometry and spark plug location and angle. Notice the centered exhaust ports to the valves vs the off set OEM one. This was on a engine dyno with 91oct
Wow.
They look really good.
I see also there is extra material around the rocker area for more strength.
A lot of work has been done.
They are so close to an LS7 casting.
Do these also work with Fast and MSD intakes?
What is the finished runner size of the Frankenstein LS3 head?
LOL I just don't want the drama. They make a nice casting for sure. Same guy that designed their stuff now works here.
I read that Cary works for you guys now.
I'm interested to see if Frankenstein will offer door stopper cathedral ports and what changes/improvements with the rest of the lineup.
Darin Morgan is over at Mast now so there are a lot of really good pro's working in the aftermarket cylinder head department.
It's good for the customers too.
I read that Cary works for you guys now.
I'm interested to see if Frankenstein will offer door stopper cathedral ports and what changes/improvements with the rest of the lineup.
Darin Morgan is over at Mast now so there are a lot of really good pro's working in the aftermarket cylinder head department.
It's good for the customers too.
How much better can LS heads get? The best dudes in the world have been working on it for years. We have traditional port inline heads flowing 420+ cfm now that’s just badass for stock style small block heads
I am curious how the LS7 heads will be in the next ten years.
I'm sure Mamo is working on something secretly which will blow us away when the time is right.
I was reading an interesting article about the optimal exhaust flow for an LS7 head in relation to the intake.
I hear between 310-320CFM would be the optimal point which is around a 75% ratio.
Would this mean better performance and acceleration if it could be done?
I would think that you would only need half the split with camshaft selection also.
It may even be a pipe dream and 4 valve territory.
I honestly don't look too much at the exhaust flow. I mean, I reference it, but it's very different from intake. The pressures from combustion when you first open the exhaust valve are far higher than the pressure in the intake manifold filling the cylinder, and then there's a piston pushing out the rest of the gases. You can open the exhaust valve a couple degrees earlier and bump compression a bit to compensate. You see the venerable AFR 205 LS1 heads with a 2.02 intake valve and a 1.600 exhaust valve. Then you move to LS7 stuff, and the intake grows to 2.2-2.3, but the exhaust valve is still 1.615 on my as yet uninstalled LS7 heads. Brodix LS7 heads are 1.614. FED are 1.615.
Don't get me wrong, making the exhaust ports less restrictive is a good thing. I like what FED did with that exhaust port making a straighter shot to the valve. But if I had to choose between a bigger intake valve or a bigger exhaust valve, I'll go bigger on the intake. And apparently, others feel the same way.
I think I saw on the Frankenstein website the exhaust ports are like 98cc or so which is a lot bigger than the OEM LS7 head of like 86 cc. I think with exhaust the flow is important but given the extreme conditions that are taking place in the exhaust stroke that can not be really duplicated on a bench at some point a well shaped larger port is going to get the job done better. I think at the end of the day you can only flow so much out of a 1.61 valve to get bigger numbers we are going to need to get to 1.7+ inches to really get the flow out without going to crazy on the head. The problem is we are out of bore room unlike todays Big Block Chevys which now can have 4.50-4.60 inch bores. It would have been nice back in 1998 when they were doing the LS1 they said hey while we are at it lets increase the bore spacing from 4.4 to 4.5 inches. Think of all the nice valve unshrouding we could have with a standard 4.25 inch bore.
I think I saw on the Frankenstein website the exhaust ports are like 98cc or so which is a lot bigger than the OEM LS7 head of like 86 cc. I think with exhaust the flow is important but given the extreme conditions that are taking place in the exhaust stroke that can not be really duplicated on a bench at some point a well shaped larger port is going to get the job done better. I think at the end of the day you can only flow so much out of a 1.61 valve to get bigger numbers we are going to need to get to 1.7+ inches to really get the flow out without going to crazy on the head. The problem is we are out of bore room unlike todays Big Block Chevys which now can have 4.50-4.60 inch bores. It would have been nice back in 1998 when they were doing the LS1 they said hey while we are at it lets increase the bore spacing from 4.4 to 4.5 inches. Think of all the nice valve unshrouding we could have with a standard 4.25 inch bore.
The number of times I've thought this...
Edit -- And Again, not saying exhaust flow isn't important. Just that it is less critical vs the intake is all.
I honestly don't look too much at the exhaust flow. I mean, I reference it, but it's very different from intake. The pressures from combustion when you first open the exhaust valve are far higher than the pressure in the intake manifold filling the cylinder, and then there's a piston pushing out the rest of the gases. You can open the exhaust valve a couple degrees earlier and bump compression a bit to compensate. You see the venerable AFR 205 LS1 heads with a 2.02 intake valve and a 1.600 exhaust valve. Then you move to LS7 stuff, and the intake grows to 2.2-2.3, but the exhaust valve is still 1.615 on my as yet uninstalled LS7 heads. Brodix LS7 heads are 1.614. FED are 1.615.
Don't get me wrong, making the exhaust ports less restrictive is a good thing. I like what FED did with that exhaust port making a straighter shot to the valve. But if I had to choose between a bigger intake valve or a bigger exhaust valve, I'll go bigger on the intake. And apparently, others feel the same way.
NA doesn’t really give a ****. Cam accordingly. FI cares about exhaust flow
07-01-2020, 08:59 AM
