Dart 180 cc alloy head as cast

[PRH]

Lets just say they are both 205cc ?

Now you’re changing the criteria.

Initially it was just 270cfm vs 300cfm....... now they also have to both be the same size.

From what I’m used to seeing, a 23* SBC head that was 205cc finished size and flowed 300cfm at an accessible lift....... that would be a pretty good head IMO.

[PRH]

These are the advertised numbers for the ATK/Profiler 210 with 2.05/1.60 valves:

Lift CFM Lift CFM
0.200 140 0.200 107
0.300 200 0.300 142
0.400 255 0.400 172
0.500 275 0.500 187
0.600 280 0.600 196
0.700 286 0.700 203
0.800 293 0.800 207

Here’s an AFR210 I tested in 2010, #1054, it was right ootb, 2.08/1.60 valves with 8mm stems.
4.00 bore/no tube on ex-

Lift———in/ex
.100— 64.8/50.6
.200—142.5/106.6
.300—203.7/157.4
.400—239.5/193.0
.500—271.2/207.0
.550—280.7/210.8
.600—276.9/213.3
.650—273.1/214.6
.700—273.1/215.9

Dart Pro 1 215 from 2009(beginning of the Platinum series?). Dart valve job, 2.055/1.60 valves, small back cut on intake valve only. Very minor bowl blend:
4.00 bore/no tube

Lift———in/ex
.100—— 69.6/46.9
.200——140.0/100.8
.300——192.5/132.5
.400——233.0/168.1
.500——263.5/190.5
.550——275.0/197.3
.600——281.5/201.1
.650——269.3/202.4
.700——263.5/204.9

Here’s a pre-platinum Dart aluminum 215......no porting, looks like the Dart vj.
2.055/1.60, no back cuts, 4.00 bore/no tube:

Lift———in/ex
.100—— 66.1/57.3
.200——124.8/102.4
.300——181.2/130.5
.400——224.4/151.2
.500——258.0/162.2
.550——271.1/164.7
.600——263.7/168.3
.650——259.9/168.8
.700——261.8/169.5

[SpeierRacingHeads]

Lets just say they are both 205cc ?

Now you’re changing the criteria.

Initially it was just 270cfm vs 300cfm....... now they also have to both be the same size.

From what I’m used to seeing, a 23* SBC head that was 205cc finished size and flowed 300cfm at an accessible lift....... that would be a pretty good head IMO.

PRH, go back and reread this thread. He is clearly throwing jabs at my build and 205cc head.

He will deny..

And here is my 205cc head.

.200 138/108
.300 204/144
.400 248/176
.500 280/201
.600 292/217
.700 302/229
.800 308/236
.900 314/244
1.00 316/247

[PRH]

And here is my 205cc head.

.200 138/108
.300 204/144
.400 248/176
.500 280/201
.600 292/217
.700 302/229
.800 308/236
.900 314/244
1.00 316/247

If I flowed that head on my bench and got similar results, I’d expect to absolutely crush 550hp with them on an 11.5:1 383 with a solid roller cam.

[PRH]

This is a cnc ported Dart iron head that started out as a 200.
I didn’t cc it, but it “looked” way bigger than 200.

This was a head that supposedly came off a Dirt motor that was built by Enders engines, probably in about 2008/2009.
Ferrea 2.055/1.60, no back cut. 4.00/no tube:

Lift———in/ex
.100—— 64.2/50.6
.200——130.5/102.8
.300——185.5/133.3
.400——225.3/161.2
.500——260.5/181.6
.550——271.9/187.9
.600——279.6/194.3
.650——283.4/199.3
.700——287.2/203.7
.750——290.3/208.2

This is the pre-Platinum Dart 215 I posted the ootb numbers for in a post above, after recutting the seats, blending the bowls, and touching up the intake SSR. No chamber work, no work at the pinch.
Still 2.055/1.60, no back cuts, 4.00/no tube:

Lift———in/ex
.100—— 68.4/59.6
.200——124.8/101.2
.300——181.2/128.1
.400——226.2/153.7
.500——261.8/172.5
.550——273.7/178.1
.600——283.1/182.2
.650——286.8/185.4
.700——284.2/188.3

The “mate” to this pre-Platinum 215 was an even earlier 215.
Well, I assume the other one was the earlier one.
It had a much smaller ex port as cast, and the intake SSR was noticeably steeper.
As rec’d that head had peak flow of 258/171.
After doing the same work to it as the newer one it was at 275/171.
The smaller ex port gained nothing.
I ended up having to match the size of the ex port to the newer head to get the numbers even close.
The intake guide bosses were quite a bit chunkier on the older head, and the owner didn’t want to spend any more $$$ chasing the flow........ so I don’t know what trimming those up would have been worth.

One thing is for sure....... Dart heads have gone thru some changes over the years.

[SpeierRacingHeads]

And here is my 205cc head.

.200 138/108
.300 204/144
.400 248/176
.500 280/201
.600 292/217
.700 302/229
.800 308/236
.900 314/244
1.00 316/247

If I flowed that head on my bench and got similar results, I’d expect to absolutely crush 550hp with them on an 11.5:1 383 with a solid roller cam.

Well it was a 10.5-1 383 with a .353 lobe and 1.6 rocker and .015 lash = .550 lift at the retainer.

As I said we made 6 pulls. Never messed with the carb because it will have an elbow and TB on it when I chassis dyno it. I've had enough engines on this dyno to know where I needed to be. It flowed 265 cfm through the carb and manifold. It accessed 262 cfm to make the 534 on this dyno.

The goal was and still is 500/500 in the car to the tires.

[PRH]

If I flowed that head on my bench and got similar results, I’d expect to absolutely crush 550hp with them on an 11.5:1 383 with a solid roller cam.

I was referring to the parameters Steve put forth for his build.
550hp would be a walk in the park with flow numbers like your 205 head.

I’ve never used a cam as small as you did with heads that good, so I have no frame of reference for that.

[SpeierRacingHeads]

If I flowed that head on my bench and got similar results, I’d expect to absolutely crush 550hp with them on an 11.5:1 383 with a solid roller cam.

I was referring to the parameters Steve put forth for his build.
550hp would be a walk in the park with flow numbers like your 205 head.

I’ve never used a cam as small as you did with heads that good, so I have no frame of reference for that.

It's all good. We have about 4 stories going on. lol

[GARY C]

Lets just say they are both 205cc ?

Now you’re changing the criteria.

Initially it was just 270cfm vs 300cfm....... now they also have to both be the same size.

From what I’m used to seeing, a 23* SBC head that was 205cc finished size and flowed 300cfm at an accessible lift....... that would be a pretty good head IMO.

PRH, go back and reread this thread. He is clearly throwing jabs at my build and 205cc head.

He will deny..

And here is my 205cc head.

.200 138/108
.300 204/144
.400 248/176
.500 280/201
.600 292/217
.700 302/229
.800 308/236
.900 314/244
1.00 316/247

Yes, I think most here know that, I was going to point that out on his first jab comment but didn't want to muck up the thread by pointing out the obvious and knowing he would not be man enough to admit it.

[randy331]

Lets just say they are both 205cc ?

Now you’re changing the criteria.

Initially it was just 270cfm vs 300cfm....... now they also have to both be the same size.

From what I’m used to seeing, a 23* SBC head that was 205cc finished size and flowed 300cfm at an accessible lift....... that would be a pretty good head IMO.

No, not changing criteria. Steve says his will be 205 ish cc and believes they will flow 270s, there was a link to a different engine with 205 cc heads flowing well over 300 cfm, so the cc are the same, or close. That was my point all along,... just cause something flows a lot,.. is it a good head ??

If all that cfm doesn't get used in the running engine ??? Why ?
Would you be better off doing a 205 cc port in a different manner that just happened to not flow as much ?
What qualifies as "good" cfm ?

Steve is reading all this and trying to make the right decisions on his engine.

Randy

[PRH]

I mean if one makes 550 hp with 270 cfm on 383 cubes at 10.5-1 hyd roller street engine and someone else has 300 and not making 550 on a similar build, which head do you want to look at to learn from ?

Why does cfm not turn into HP some times I guess is the question ?

No mention of runner volume, or Steve’s heads..... which aren’t even done yet.

You can’t imagine a scenario where a 270cfm head beats a 300cfm head on a 10.5:1 383 with a small cam ...... but isn’t as good as the 300cfm head on a higher effort 13:1 427(or a 13:1 383)?

Steve is reading all this and trying to make the right decisions on his engine.

My guess is Steve will forge ahead, gathering data from his testing, and will make choices based on what makes sense to him, for the goals he’s set.

He bought a flow bench so he could try and learn to figure it out.

I’m sure he’ll get way more out of that than what’s in this thread.

[SpeierRacingHeads]

What Randy doesn't understand, and I'm not sure why, If both heads are 205cc and one flows 270 at desired lift and then stops and the other flows 280 at desired lift and carriers the flow curve all the way until the valve touches the retainers, the second head is always better and more versatile.

The porters vision and ability to get the shape correct to carry the curve is critical in making power.

Thinking all you need if flow to your lift is correct, better do something more than 550hp engines.

Not one mention of velocity in this senerio. Always cfm.. Thought the difference was explained a long time ago.

[brentry]

Afr 195 head is 260cfm at 400 lift.so it says . From pics ,looks like short turn is sorta/kinda like a 243LS.
Now the question ,do these really add alot more pwr to the curve compared to a different type,lower height,ess cfm short side .

[SpeierRacingHeads]

Afr 195 head is 260cfm at 400 lift.so it says . From pics ,looks like short turn is sorta/kinda like a 243LS.
Now the question ,do these really add alot more pwr to the curve compared to a different type,lower height,ess cfm short side .

Prime example. I can take that head off, not change one thing on the shortblock, slow the airspeeds down, and find 20+.

Do this everyday.

[digger]

What Randy doesn't understand, and I'm not sure why, If both heads are 205cc and one flows 270 at desired lift and then stops and the other flows 280 at desired lift and carriers the flow curve all the way until the valve touches the retainers, the second head is always better and more versatile.

The porters vision and ability to get the shape correct to carry the curve is critical in making power.

Thinking all you need if flow to your lift is correct, better do something more than 550hp engines.

Not one mention of velocity in this senerio. Always cfm.. Thought the difference was explained a long time ago.

i don't know much, but i know enough to be able to know that you cant say one head is better than another based purely on the flow curve and be correct 100% of the time