Ever since the newly introduced set of Dart Aluminum SHP 200cc heads there has been a bit of talk with no real testing (to my knowledge). Eric had posted up a thread with pictures of a set he worked with and I had mentioned we had a set on the way for a customers build. After this Eric contacted me and we decided that we would build our customers engine (specs below) heads untouched and we would than test/ship the heads off to Eric for a little clean up so he and everyone else can see what they are capable of with a little work. I will let Eric speak for what he is going to do to them after he speaks to Mark Johnson whom runs the shop here at ATK.
Let me say, this is NOT a MAX EFFORT deal. This is a street warrior engine that may see the track from time to time for our customer and anything over 500HP is icing on the cake. Below are some pictures of the build and STOCK heads out of the box, as you can see, you can quickly pickup some power with minimal work.
Engine Specs:
#880 Block 4bolt Block 1pc Seal
Scat 4340 3.750" Forged Crank
Scat 4340 5.7" H Beam Rods
10.1 Mahle Forged Pistons
Dart SHP 200cc/72cc Aluminum Heads (out of the box)
Hyd Roller Cam 247/253 @ 50 .602/618 112LSA
Crane 1.6 Roller Rockers
Edelbrock Air Gap Intake
MSD Pro Billet Dist
MSD 8mm Wires
Quick Fuel Q-750 Carb Jetted @ 72/82
Best ran at 36 degrees of timing
ENGINE PRODUCED 515HP @ 6000 RPM / 503TQ @ 4700RPM We ran up to 6200RPM on other pulls, but this was our final adjustment dyno. From 6000-6200 was pretty consistant and slowy started to dropped off at 6200RPM. I have a PDF File of the dyno to post, if anyone knows how???
thats a lot of duration for only 10:1 and a dual plane
I'd like to see what it would do with the heads ported and a Super victor
with plenum work, and milled heads to bump the comp a bit.... another 50-75hp!
Definatley, but like I said...its a street car. You can always do more, but its application for us. ERIC will be recieving the heads in 2-3 days to do a once over on them. We will be posting the after results once we get them back and dyno it. :thumbsup:
WE GOT A BONUS! To do a accurate comparison, we will be running this whole setup with Pro-Filers as well out of the box 195cc. This will be a nice back to back comparison for all to see. Should have this done Mon or Tues of next week.
I am excitied to get a chance to do this. I would really like to thank the guys from ATK for giving me a chance to play with the heads and see what a little grinding will do to these heads.
I plan to do a basic port job. I will not be doing anything crazy. This is a street motor. I plan to do each section then flow it so you guys can see how much grinding one section can gain. The plan goes is to grind the chamber, throat, bowl, shortside, guide thinning, gasket match, and pushrod pinch. Not in that order. This probably sounds extensive but I don't plan on opening it up a ton. I am going to try to time how long it takes to grind these. I am not the fastest porter but it should give guys out there an idea of how much work goes into a head. I will try to share as much information about what I am doing as possible. I am going to be a open book.
I am just going to have fun grinding these heads I have no expectations but I am hoping for some good numbers.
Any idea what this work is worth in real dollars. Seeing these SHP heads are Econo heads costing just under 1 grand. The out of the box AFR heads are selling for just under 1500. Price in most cases will dictate which head is a better bargain. Because if money wasn't a issue we wouldn't be talking SHP.
Eric will have to post up what his time is worth/retails for. We would normally charge $200-$300 for something like this, but were not a small shop.
The biggest thing though...were not comparing these to a $1600 head and we are not trying to modify these to compete with a $1600 set of heads. This was moreso to see what type of power they are capable with out of the box. Eric doing his work was just a bonus for our customer and gave Eric a chance to work with a set. The good part is, that a customer may not have that extra $600-700 in his pocket for AFR heads....he can buy these and have someone work them over a year down the line when he can afford to do so, while making great power now with an American Made head. $ is just about always an issue...im glad to see these heads work well....it will nice to see how the Pro-Filers compare back to back as well since they are at the same price point.
Because the air speed is too fast, after the chamber porting it now roars on the bench. It is doing this because now it is moving more air through the same sized port. More info comming tonight.
I have to commend you for the work and time you are putting into documenting this work. Many just don't know the effort and hours that goes into a correctly sized port.
Big numbers don't always make power. there have been many heads I have flowed and checked velocity to see they are already to big for the given motor application.
This is a great test to see how the SHP 200 heads respond to porting, I will guess the port will be about 210cc when done and should flow in the high 280's sized for the 383 spinning about 6500-6600.
Ground bowl to 94.5% it will probably ended up 95% when the port is finished. I did exhaust bowl too but I never measure it I just know the shape I want and feel it until it is there.
Then I smoothed the area around the guides
INT EX
.1-67 57
.2-141 107
.3-195 141
.4-235 172
.5-264 187
.6-258 196
.7-259 200
.8-262 201
.9-262 203
.95-263 218with pipe
Time to the bowls for one head 1:10
Time to do the area around guides for one head 1:11
Notes:
The flow numbers were not stable at all the would jump from 272 to 259cfm. The reason for this is because when you do one thing it affects other areas. The shortside was marginal before the changes but now it is not right. You fix that then the pushrod pinch is a problem. Anyway don't worry still have a lot to get done.
The bowl is not blended into the throat because I haven't done the throat yet. So that creates a funky transition from bowl to throat. The short side area when it is finished will probably see the most gain because all areas will be tied together. I typically don't flow a head until I am done with it or have just finished the shortside.
Tomorrow will be throat stopping at the short side( I will do the throat at the shortside when I do the short side) after that shortside then pinch.
When porting a head, how much variation if any do you see from each intake and exhaust port? I would imagine that the casting would also have an effect on this too.
Good question. I am right handed and sometimes I find it very hard to copy a design going from doing on my right side to my left side. However if you measure often the ports end up very close. Sometimes I think for sure there is going to major differences in flow but then they end up flowing close to the same. I will say even if their is difference I don't get too worked up because because I can promise that the ports will not flow the same one the intake manifold is attached. Another thing to think about is the long and short runner of the BBC heads never flow the same.
Well guys....here it is....the PRO-FILER head test :thumbsup:
The Pro-Filer picked up 17HP & 10TQ over all and an average of 12HP/12TQ through out the RPM Range. These are both great heads by american made companies. The Darts retail for $930 a set and the Pro-Filer $1090.00. STOP USING OFFSHORE JUNK and support these Proven American Companies. I have both heads if anyone needs a set :thumbsup:
The next test will be once we get the Darts back from Eric. We will test the after results :hurray:
Gasket match and pinch ruffed in. This is a 1205 gasket size. Pinch CSA now 2.20. I can't go much further without getting to thin. Mark didn't want the wall less than .060 so I really cant go wider and with the 1205 gasket I can't go taller, so it is what it is.
Speed over the short side 403fps
Fastest at pinch 393fps center 335fps
Time to do this for one head and flow it 1:32
Next part comes the beautification process. Where you make things look good. The numbers from here will not move around much either way. I will also finish work on exhaust
That is a good increase, I figured the SSR was not right with your .600+ numbers suffering so much. .600+ plus really picked up to make a healthy port.
Are you going to cc the runner when all said and done?
I hope some see that it takes a good understanding of air speed that really makes the port work in the end, and that working one area may or may not help much overall.
Looks like your still pretty fast over the short turn, but it seems to be hanging on throught the lift. With the runner size and motor size, this should really make wake up the combination.
At this point you really can't do anything. I like to see in the shortside speed in the 390s but if I did that here what it would do is flow more air but the air speed at the pinch would increase above 400. I don't like that idea so it is what is besides it is a street engine turning maybe 6500rpm not a race motor going 7000-7500rpm.
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