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So I'm hung up on my next engine combo... I've narrowed it down to a 416 based LS3 platform (eschewing a blower for the time being).
The 416 looks like this:
GM LS3 Aluminum Block Machined and Prepped
Compstar 4340 Forged 4.000” Stroke Crankshaft
Manley 6.125” 4340 H-Beam Rods w/ARP2000 Bolts
Wiseco 2618 Forged 4.070” Pistons w/-3cc Flat Top
Wiseco NPR Stainless Steel Top Ring Package
Clevite H Series Main & Rod Bearings
Dura Bond Cam Bearings
ARP Main Studs
Cloyes Hex-A-Just Timing Set w/C5R Chain
Ported Melling 10295 Oil Pump
Goal of 11.8:1 CR on 93 octane w/Cometic .040s and "Zero Deck" height
Okay, good. Now... the plan. I plan to sell my current motor complete from pan to intake. Ready to roll. I'll keep my fuel rail, injectors, and ATI balancer, and my Kooks 1-7/8" Headers and 3" True Duals. I'll use that money to help fund the new motor. I also want to keep my CircleD 4000 stall and the FLT Level 6 4L65E alive (means HP and RPM need to be kept in check - so 700rwhp or 7000ish RPM limit). I could swap a lot of that, but that's not the point. I built a lot of the car for a future 402/416 swap and don't plan to completely gut the car. It just so happens that buying a $5k shortblock and having to add a lot of the LS2 swap components as well as a new cam make it no more cost effective than just selling off my current motor and going with an optimized combo.
So, my two combos are not far off in price (surprisingly) and are as follows:
Now, there are things I like about them both. But let me provide my rationale for building the combos as I did.
Option 1 I chose the LS3 heads (which are really just LS7 heads with the wrong manifold) and hydraulic roller. Why that? Well, the LS3 manifolds are somewhat limiting until FAST comes out with the new interchangeable runners, so that screams to me, hydraulic roller and less RPM. But instead of moving to a cathedral port, the TFS LS3 heads offer so much more airflow, that a much milder cam can be used to create similar power. The 416 seems to be limited around 650HP here with either cathedral or rectangle port heads when using a FAST and hydraulic roller. Either way, the pricing between all the aftermarket options TFS, MMS, PRC, or MAST are all pretty close.
I understand I'll be giving up some power here, but I also think for a street car that sees a lot of action on the street, this is a very solid setup. Brian Tooley would be providing the top end here and he works the TFS 255s with some cleanup, adds the TEA/REV Hollow-Stem intake valve (100g), and adds his springs. I then would top off with his cryo-treated LS3 rocker arm package with the upgraded trunion kit (since the TFS heads include PM guides out of the box). I'd also go with the Johnson lifters with axle oiling (non-short travel) as I won't be ripping super high RPM here. So the regular limited travel lifter will be perfect. I have the short travel ST2126 now and they are hands down the best hydraulic lifter for the LS platform.
Overall, this would be a package that I could set and forget and still make great average power than would probably peak around 6400 and be done by 6800 or so. So this would work well with my current drivetrain and stall and hit my goals of providing a reliable, streetable powerplant.
Option 2 I eschewed hydraulics in favor of the LLSR because of the LS7 manifold and heads which carry power to 7000 easily and possibly more. However, the cam is still pretty streetable and shouldn't have to carry out that far to make power - again as a limitation of my drivetrain. Everything there supports the LLSR. It should be plenty reliable with stainless steel rockers (incredible pieces from Crower) and pretty stout solid rollers with axle oiling from Morel. I've weighed maybe going to a bushed lifter here to take the abuse on the street, but I've heard mixed things there.
The MAST heads are the best on the planet, so I wouldn't be giving up anything there. But with the 416 and the relatively mild solid roller, I still might only be looking at 675HP here. The FAST still is a limit, but not nearly as bad as the LS3 variant. Going to a single plane might help or to the short runners in the FAST, but I want overall average power since it's a street car and still only a 4000 stall converter.
As I type this, it's pretty clear where I should go, but wanted to see what others thought.
Don't get me wrong Jake, the MAST stuff is like the blue pecker pill to your intellectual ego; BUT.......To me if your guesstimate of roughly 25 more flywheel horsepower is close to accurate, then the added lift/spring fatigue/rpms just aren't justified for your use. If you were NHRA class racing then yeah, but for a street car; I like you prefer the "set it and forget it" low maintenance. Plan it, build it, drive it. **** checking this that and the other thing all the damn time.
I'm not saying a LLSR is the only part of that statement as they seem ultra quiet with low maintenance, but the added .100" valve lift IMO does not show up in the head's flow which tapers off. Thereby shortening spring life for just a few cfm.
Also the piston speed gets pretty high in a 4" stroke when going from the 6700 range to the 7100 area.....so things like rings/bearings/skirts/cylinder walls ALL take the brunt of that elevated rpm
In a nutshell, I really like your option 1.....but that's just me.......
If I were going for more RPM, the LS7 would win everytime. I haven't really considered playing with the MAST LS7s and a hydraulic setup... The flow between the MAST 255s, 265s, and the TFS 255s are all pretty close. They all run essentially LS7 "guts" with similar valve angles, LS7 length valves. I know this because the roller rocker options are interchangeable between the MASTs at least. The FAST LS7 is so much better that it is where any additional power would come from. Not the heads themselves.
I do like Tooley's 239/254 114 cam... it's barely bigger than what I have in my 346. So it should drive nice.
And yes. I'm still an advocate of the LLSR. Which is why it's an option
I personally think on a 416 cubic inch motor a TFS/BTR 245 cathedral head with the nitrous exhaust port and finish hand blending finished be Brian Tooley with a cam matched by him will walk all over option number 1. Erik @ HKE built a 457 cubic inch LS2 sleeved motor with the 245 TFS head with a fast intake and a hydraulic roller ... 725 plus horse at the crank was made on pump gas.
Why ? Simply because UNDER THE CURVE power is where it's at and what win races. That head continues to stop some larger runner heads at the track.
Option 2 would be nice in a older car where the cowl hood wasn't a pain in the *** but unfortunately that's a F body flaw. Changing the spark plugs is a headache it'll kill me to take the valve covers off every 1000 miles or so.
So here's a test that was done between MAST 245s and the 255 LS3s (similar to the TFS heads) on a 408 (bore restriction might be hurting things here) but the bigger issue is the FAST manifold is obviously limiting the LS3... the MAST 245s are on par with the TEA 245s I would imagine. Torque @ 3K is a loss for the LS3, but power under the curve isn't much different (with a 4K stall I don't care about 3K losses). Now yes it's a 239/255 114 cam, which favors the LS3. But cathedral ports don't care and typically carry power uptop more with additional exhaust duration. Either way... looks the same with the LS3 heads being a little stronger in the midrange. I'm sure they drive similar too. 640/580 with either head in that less-than-optimized magazine test.
If only the MAST 265 LS7s with the FAST LS7 had been tested as well...
Wow I'm even surprised the cathedral head did that well with a cam with that much split.
Jake, Tooley have said it in this in the past "the wider the duration split the more the low rpm speed will suffer".
That's the whole problem with that test you just mentioned. Only way I would ever do that much split with a cathedral head if I was go do a big shot of juice with a alot of stall.
On another no one knows a TFS cathedral head better than Brian Tooley. He designed the head and knows what duration the "sweet spot" is achieved at. Caprice posted a thread where a 100 dollar 317 head was even better than a LS3 head till 4000 rpm.
So here's a test that was done between MAST 245s and the 255 LS3s (similar to the TFS heads) on a 408 (bore restriction might be hurting things here) but the bigger issue is the FAST manifold is obviously limiting the LS3... the MAST 245s are on par with the TEA 245s I would imagine. Torque @ 3K is a loss for the LS3, but power under the curve isn't much different (with a 4K stall I don't care about 3K losses). Now yes it's a 239/255 114 cam, which favors the LS3. But cathedral ports don't care and typically carry power uptop more with additional exhaust duration. Either way... looks the same with the LS3 heads being a little stronger in the midrange. I'm sure they drive similar too. 640/580 with either head in that less-than-optimized magazine test.
If only the MAST 265 LS7s with the FAST LS7 had been tested as well...
Another thing to think of is if you did go cathedral you could keep your intake and rockers. I think you already have a FAST 102 with your current setup? Not sure on your rockers.
I do have a FAST 102 and stock rockers with trunion upgrade. I wouldn't keep the rockers - I'd just sell as part of the longblock. I could keep the FAST however and run cathedrals.
Also, from that same test, they did run a 239/247 "cathedral port" split. From Super Chevy, "Equipped as such, the cathedral-port heads and cam combo pumped out 631 hp and 575 lb-ft of torque... Having dialed in the combination, we proceeded to swap out the cam. After installation of the rectangular-port cam, the peak power numbers improved slightly to 639 hp and 578 lb-ft. The increased exhaust duration offered by the rectangular-port cam (255 degrees versus 247 degrees) improved power production slightly from 5,500 rpm on up, but the improvements in top-end power came with a penalty. The increased exhaust duration had a negative effect on low-speed power, as power was down from 3,000 rpm to 4,700 rpm, the greatest difference of 20 lb-ft coming at 3,100 rpm."
"Run with the Mast CNC LS3 heads and Comp cathedral-port cam, the 408 stroker produced 634 hp and 577 lb-ft of torque, meaning a difference of just 3 hp and 2 lb-ft measured peak to peak. In reality, the cathedral-port heads were within 1-2 hp at the peak, but offered as much as 20 additional lb-ft below 4,000 rpm."
I know Brian talks about coefficient of discharge a lot and so does Tony as to why the cathedrals do so well in comparison, but I still think if the FAST LS3 intake wasn't garbage, that the test would show a bigger gain for the LS3 heads. That's why we see a lot of 700+HP combos when using different intakes with the LS3 heads. Unfortunately, that's sort of where I am... which is why option 2 looks good... or if FAST ever comes out with the interchangeable runners...
I do have a FAST 102 and stock rockers with trunion upgrade. I wouldn't keep the rockers - I'd just sell as part of the longblock. I could keep the FAST however and run cathedrals.
Also, from that same test, they did run a 239/247 "cathedral port" split. From Super Chevy, "Equipped as such, the cathedral-port heads and cam combo pumped out 631 hp and 575 lb-ft of torque... Having dialed in the combination, we proceeded to swap out the cam. After installation of the rectangular-port cam, the peak power numbers improved slightly to 639 hp and 578 lb-ft. The increased exhaust duration offered by the rectangular-port cam (255 degrees versus 247 degrees) improved power production slightly from 5,500 rpm on up, but the improvements in top-end power came with a penalty. The increased exhaust duration had a negative effect on low-speed power, as power was down from 3,000 rpm to 4,700 rpm, the greatest difference of 20 lb-ft coming at 3,100 rpm."
"Run with the Mast CNC LS3 heads and Comp cathedral-port cam, the 408 stroker produced 634 hp and 577 lb-ft of torque, meaning a difference of just 3 hp and 2 lb-ft measured peak to peak. In reality, the cathedral-port heads were within 1-2 hp at the peak, but offered as much as 20 additional lb-ft below 4,000 rpm."
I know Brian talks about coefficient of discharge a lot and so does Tony as to why the cathedrals do so well in comparison, but I still think if the FAST LS3 intake wasn't garbage, that the test would show a bigger gain for the LS3 heads. That's why we see a lot of 700+HP combos when using different intakes with the LS3 heads. Unfortunately, that's sort of where I am... which is why option 2 looks good... or if FAST ever comes out with the interchangeable runners...
Test with cathedrals and a good intake show higher numbers as well. The FAST really sucks for peak HP. Buts it just about all we got in the f body.
I actually speaks with Brian Tooley on the phone I know at least twice a month on the phone. He have told me more than once that on dynos these big runner heads outshine cathedrals but in the real world at the track and on the street they just don't accelerate like smaller cathedral head does....
After all its a member on here runs 9.50 in the quarter using TFS heads in naturally aspirated form with a FAST intake on pump gas in all motor form in a F body.
I've yet to see this achieved or matched as I study all motor builds more than a regular guy do. Turbos, blowers and nitrous just don't float my boat. On that note..... However Tim (Gray86hatch) or something like that on here had went 9s using a factory L92 but the car was a lighter foxbody and the car ran a single plane type intake but it was on pump gas also.
I just worry that the plastic intake manifold homogenizes the performance to the point that it doesn't matter what heads you run.
I had a thread before about just reusing my TEA heads on a 416. I bet with the FAST on top it would dyno within 15-20HP of anything else. And on the track it would be whether or not I took a **** that morning if it was faster or not.
I know the head designers/porters don't like to admit to it. But as long as people continue to produce awesome heads and then cap them off with crap plastic manifolds, this is what happens. I wish companies would produce a manifold that would fit the cowl of the F-Body or under a Vette's hood and allow for actual cfm greater than 300cfm through the manifold.
Otherwise, 600rwhp seems to be about where it is... LS7 or Cathedral. You might get a little more, but that seems to be the limit of the FAST with anything under 440cid.
Which is why I'm going nuts trying to spec out something.
I was even looking at the AI ported TFS 230cc heads. $2500 with PM guides and BTR springs and it flows 340cfm. Would be a good street head on a 402 or a 416.
When I was looking at heads, I was hung up on mid-lift flow numbers. I really wanted a head that could go 280+ @ .400". The people who really influenced my decision were of the mindset that cross sectional area was where it is at. I ended up getting both.
Yeah... those Darts look good. The MAST LS3/LS7 and TFS LS3 are in that same universe on the medium bore stuff. The MAST stuff is in the 290s @ .400 and TFS is close.
11-23-2015, 07:43 PM
It's Christmas for me? 
