SPS LS3 Cylinder Heads
Check your mail KW Baraka.
Last edited by Wiliam Munny; Apr 14, 2017 at 06:34 AM.
Also, recall, the formula for coefficient of discharge is as follows: C/D=airflow/curtain area. Curtain area=valve diameter x Pi x Lift.
Avg from .200-.600:
TFS 245.....SPS Haymaker.....TFS 255.....MMS235
104.79......104.94................100.07.......101 .33
And for the hell of it, my TEA Stage 2 LS6 heads were a 99.46.
Based on published flow numbers. So inflated cfm ratings can alter this. But you can see something here. All these heads are pretty close on avg. So they are all similarly efficient in terms of valve to flow. Which matters more than port size. If you have to stick a huge valve in the head to flow... you end up with softer numbers despite a huge flow advantage - see LS3 heads.
However, this is just .200-.600. When you start looking at .700 numbers the larger heads with larger runners and larger valves start to flex their muscle. Because they are flowing more air and are starting to become more efficient at that point. You just have to run a cam to take advantage of the added curtain area and airflow potential.
Avg C/D
101.48 TEA 255
106.42 TFS 235
106.57 TFS 245
101.48 TEA St2
103.52 MMS 235
104.94 SPS Hay
101.01 MAST 255
102.61 MAST 240
Made an edit - had the .55 numbers in there for some, which brought down the overall efficiency as it was another data point that others didn't have. So not a true apples-to-apples comparison.
Last edited by JakeFusion; Apr 14, 2017 at 09:33 AM.
Also, recall, the formula for coefficient of discharge is as follows: C/D=airflow/curtain area. Curtain area=valve diameter x Pi x Lift.
Avg from .200-.600:
TFS 245.....SPS Haymaker.....TFS 255.....MMS235
104.79......104.94................100.07.......101 .33
And for the hell of it, my TEA Stage 2 LS6 heads were a 99.46.
Jake, can you figure mine for me. Here are the flow numbers:
Avg C/D
101.48 TEA 255
106.42 TFS 235
106.57 TFS 245
101.48 TEA St2
103.52 MMS 235
104.94 SPS Hay
101.01 MAST 255
102.61 MAST 240
103.18 Ai Dart
.700 numbers
78.34 TEA 255
80.25 SPS Hay
78.13 MAST 255
77.17 MAST 240
71.39 Ai Dart
The Best V8 Stories One Small Block at Time
But it's interesting to compare heads like an LS3 to a Cathedral where they would be flowed on a 4.125" bore. And the cfm numbers are fairly similar. But the cathedral port head is more efficient - doing it with less valve and probably less runner volume. So the velocity and airspeed are higher. So you get better cylinder fill. And thus, more power. And then you look at something like the MAST 285 LS7 heads... and they are more efficient and flow a lot more everywhere. And the larger runner supports a larger motor and more RPM. So for an NA motor, the LS7 head is still king. Then Cathedral. And then I think LS3s are somewhere below that. Though the new SPS heads look promising.
With an FI motor... go with the highest possible cfm rating and largest valve. It'll support more boosted power. And this is where an LS3 head makes some sense as it can flow more than the cathedral port. But for a motor that relies on pressure differential and intake velocity, the more efficient the head, the more real world power it makes.
The SPS Haymaker uses a smaller valve to create flow numbers similar to TFS 255s and MAST 255s... but does so with a little more CSA. I think that's probably a good trade off. Uptop it doesn't lose flow but down low, it creates more velocity with the smaller valve.
Last edited by JakeFusion; Apr 14, 2017 at 10:16 AM.
he hosted a raffle for CNC Port service on a set of 243 heads, I entered, won. I opted for 1100 in extras (valves, BTR cam kit through him, lifters, lifter trays etc), was told 3 weeks after he got my heads. took in reality 5 weeks to get heads back, one was mine, was was not. One head had 3 2.02 intake valves, and a 2.04 intake valve. none of the valve seats were cut even close to properly, 55% leakdown when bolted to my block. took 2 more weeks to figure out the rest of the bullshit. (never did get my original head back). in the end he refunded me only $120 to have a local shop cut the seats again, sent me 8 valve stem seals, and one head gasket. I'd not do business with him ever again.
I have video, Pictures, and copy of the entire conversations for proof.
Last edited by Ironhydroxide; Apr 14, 2017 at 10:53 PM. Reason: Clarification.

My current LS3 heads are from Frankenstein. I had them do a somewhat custom combination for me which created a 'smaller' (compared to his normal program) intake port size and valve size, all based on a TFS GenX casting. The runner is 275cc and the intake valve is 2.175".
The average as you generated it from 0.2" to 0.6" is 103.157. At 0.7" the number is 81.538.
I have data for another set of heads from MMS, his new LS7 port using the TFS castings. These ports are 265cc, and I think these numbers are based on using a 2.20" intake valve.
The 0.2" to 0.6" average for that head is 106.210. At 0.7" the number is 83.505.
I don't know how LS7 heads in general compare to LS3 heads in this metric, but that's the data that I have...
lots of hogged out crap that looks pretty makesa big peak # and either turns into a sprinkler system or the car runs lke a pooch
then guys crutch it even further with too big a cam goes even slower
Unfortunately the web geeks worship #s
Own a set of heads that Mamo did yrs ago he could got way more # but it would have been too big for example....most porters just figure you wont know any better and do what they got to in order to pay bills.

My current LS3 heads are from Frankenstein. I had them do a somewhat custom combination for me which created a 'smaller' (compared to his normal program) intake port size and valve size, all based on a TFS GenX casting. The runner is 275cc and the intake valve is 2.175".
The average as you generated it from 0.2" to 0.6" is 103.157. At 0.7" the number is 81.538.
I have data for another set of heads from MMS, his new LS7 port using the TFS castings. These ports are 265cc, and I think these numbers are based on using a 2.20" intake valve.
The 0.2" to 0.6" average for that head is 106.210. At 0.7" the number is 83.505.
I don't know how LS7 heads in general compare to LS3 heads in this metric, but that's the data that I have...
The Mamo TFS LS7s are very nice. Being that they use the same valve and a smaller runner than the MAST 285s and make comparable numbers in terms of efficiency and flow is why you see a lot of Vette guys with 630+rwhp numbers from that head and relatively mild cams on the 427.
And to be honest, I trust Tony's flow numbers more than MAST. Whenever a magazine runs their flow numbers, they are always lower than the MAST advertised numbers (and we know how magazines can inflate things sometimes). But pumped up flow numbers impacts the C/D.
I agree that the LS3 heads with flow numbers on a 4.150 bore isn't fair since many never see that size bore without a block upgrade so that unshrouding of the chamber aids to the inflated numbers by SPS, what do they flow on a 4.070 bore or even a 4.125 bore? guessing that turbulence hurts their numbers, so they advertise numbers that NEVER really happen...
I could be off on my thoughts, always learning and thinking, even if its way out in left field....
Too small of a runner you worry about leaving power on the table... Too big of a runner and your low end grunt will suffer and the power curve will look crap.










