Dart/Summit Vortec heads VS SGD Vortec heads
I am in the process of getting parts and a GM crate motor to put into my RV. I decided to go with Summit Racing Vortec heads..There is not much info on these heads and over the last month, or so, I decided to really dig into the internet and find the information I have desired...I found this information, since several have said that these heads are not as good as original GM Vortecs...Well, Chevy High Performance Mag did an article on ALL the vortec heads available out there. Here are the results from the Summit/Dart vortec heads:
From CHP mag
"Now for the aftermarket. Dart Machinery is a high-tech company that uses its knowledge in NHRA Pro Stock racing to develop cylinder heads, blocks, and intake mani-folds for the high-performance enthusiast. Initially, we were told that Dart wasn't interested in competing in a power test because this particular head was not designed as a power piece. Instead, it was conceived as an inexpensive OE replacement for major engine rebuilding facilities across the country, and that given the end user, Dart racing technology was not incorporated in this casting. After numerous phone calls and a promise that we would be clear about the head's intention, Dart decided to join in the fun. We figured it would be interesting to see how well this OE replacement head would fair against performance pieces that were designed to make power.During the assembly session there was a sense of uneasiness in the dyno cell as each of us had our opinion as to how the Dart head would do. One felt that the 165cc intake runner would limit intake flow while another thought that the 3cc (0.3:1 compression difference) larger combustion chamber would hurt torque across-the-board. The Dart and Vortec both have center-bolt and perimeter-bolt valve-cover patterns, screw-in rocker stud bosses (studs not included), and feature the nicest raw casting of the bunch. Soon enough, the engine was ready and we pulled the handle.Low-speed torque was down a hair, 361 lb-ft at 2,000 rpm, but peak torque was 424 lb-ft at 4,000 rpm. Peak horsepower was 384 at 5,400 rpm, showing a definite restriction in intake runner size. What's interesting is that the little 165cc intake runner was able to consume a whopping 633 cfm at its highest point of volumetric efficiency. This told us that the small runners were restricting air through the cylinder head becuase the actual ports themselves were moving all the air they were given. Without a doubt, these heads would see a major improvement with a little polishing around the valves and porting the intake runners to match the intake gaskets. The average numbers were 393 lb-ft of torque and 289 hp across-the-board. Considering these heads weren't designed for performance, they did quite well."
RPM TQ HP
2,000 361 137
2,200 360 151
2,400 368 168
2,600 375 186
2,800 383 204
3,000 391 223
3,200 400 244
3,400 408 264
3,600 416 285
3,800 421 305
3,900 423 314
4,000 423 323
4,200 422 338
4,400 418 350
4,600 410 360
4,800 402 368
5,000 393 375
5,200 384 380
5,400 373 384
5,500 366 383
5,600 357 381
5,700 347 377
Average: 393 289
Advertised AirflowMeasured at 28 inches of H20
Lift Intake Exhaust
0.100 NA NA
0.200 126 108
0.300 185 128
0.400 221 136
0.500 232 138
The airgap intake was used in a 355ci motor and a crane roller cam was used. Grind #119831 @.050-222/230 w-.509/528 lift
Below is the Scoggin Dickies vortec head for comparison :
From CHP mag
"We ordered these heads from Scoggin-Dickey fully assembled and with a maximum valve lift good for 0.545-inch. The cool thing about the Bow-Tie Vortec head is that that it features both center-bolt and perimeter-bolt valve cover mounting bosses, plus, "Vortec" is cast into the head above two of the spring perches and a neat little Bow Tie Chevy emblem in the exhaust face of the cylinder head. The ports look very similar to the OE Vortec castings but are obviously designed to make power for the die-hard street enthusiast. Scoggin-Dickey also offers a large-runner 203cc Bow-Tie Vortec head for the high-rpm enthusiast.The OE Vortec heads feature pressed-in rocker studs, whereas the Bow-Tie version comes with 3/8-inch screw-in studs. We checked each stud to make sure they were torqued, lashed the valves, and set the fuel and timing at their previous settings. Soon, the dyno showed 365 lb-ft of torque at 2,000 rpm, and moments later revealed a new best torque number of 434 lb-ft at 4,000 rpm. The peak horsepower numbers also screamed performance, boasting another best number of 399 hp at 5,400 rpm. Our dyno airflow meter showed almost a 20-cfm gain in airflow usage because these heads consumed 652 cfm at their volumetric peak. The larger 750-cfm Speed Demon shined as the power numbers began to rise. Looking back, we were sure that we could have squeezed one more horsepower by cooling the engine or altering the air/fuel mixture. Overall, the average power numbers displayed a stout 403 lb-ft of torque and 294 hp. Porting and polishing these heads would most likely reveal a bit more power, but we decided to save this test for another day."
RPM TQ HP
2,000 364 139
2,200 364 152
2,400 372 170
2,600 381 189
2,800 390 208
3,000 398 227
3,200 411 258
3,400 416 269
3,600 424 291
3,800 430 312
4,000 434 330
4,100 434 338
4,200 433 346
4,400 429 359
4,600 422 370
4,800 420 380
5,000 407 388
5,200 399 395
5,400 388 399
5,500 381 399
5,600 365 397
5,700 365 397
Average 403 294
Advertised Airflow Measured at 28 inches of H20
Lift Intake Exhaust
0.100 71 53
0.200 139 102
0.300 182 131
0.400 224 146
0.500 248 161
Well, even tho Dart did not intend to custom the heads, they were only down by 10 hp from the SD vortec prepped heads.. valve guides and springs...Not too shabby!
Last edited by Dannyringo; 03-21-2012 at 06:26 PM. Reason: change name of article
consider this about these heads
They are a very good looking casting according to the testers of the head and they might be a good secret type of economical build when considering purchasing the Summit/Dart head...I really thought about going with the GM heads, but could not validate the money going out...The base head still had pressed in studs and although they are good to .460 lift without troubles, I really would prefer the screw in studs of the Summit heads...Plus with the thicker casting and I live in Arizona where the heat can be upwards of 120+ outside, what kind of temps under the hood, plus all the mountain ranges leading from a low of +800ft to 7,200ft climb~! Standard vortec heads I don't think will live very long down here...Just my opinion on it, though.
The Magazine testers stated that they were surprised with the performance that they did...In fact if you really look at the facts, they were down by about + or - 10 to 15 horse power and they admitted that if they were ported they would perform....
The Dart heads are a better head than the limp Smog 305 heads any day of the week~! They meet or exceed the 461/462 head...Thats all that matters...Tq rules on the street not high revving motors from stoplight to stoplight~!
Scoggin Dickey Dart/Summit head
TQ HP TQ HP
2,500 364 139 361 137
3,000 398 227 391 223
3,400 416 269 408 264
4,000 434 330 423 323
4,400 429 359 418 350
5,000 407 388 393 375
5,500 381 399 366 383
Now you can't tell me that those 305 heads will out preform both of these heads...Notice I only went to 5,500 rpm on the chart...That is realistic values on the street for racing...Also not the lift of the cam they used. It was .509/525 lift with 222/232 d @.050 or 284/292 advertised duration....Even the Vortec head has met its max breathing ability with this cam....A smaller cam in the .468/495 lift will out perform this cam at the given rpm, an airgap intake with a 600cfm, or 650 cfm carb.... In fact in a recent test the Com cams 252 cam made a max of 392hp/420Tq with a 600cfm carb and Vortec heads.
Smaller is better
Last edited by Dannyringo; 03-21-2012 at 10:32 PM.
maybe its all about you making money with your porting...If a person does not have this experience like the other person said he did not, then all he would be is a target for people trying to take advantage of him and his wallet...I am all about not going to people like you with all of your so called knowlege...I have seen people get ripped off by many a vendor telling them that they know this and that ....SO i guess your as good as the Dart team Or
RHS? I doubt it
Like I said, you and all of your knowledge don't mean nothing to me....
I think your brilliant...your using smog heads and porting them....spending all of that cash...you said you put $1,000 bucks into your vortec heads...500 bucks into your 305 smog heads...I paid 585 with shipping for brand NEW Dart heads with stainless steel valves, comp 985 springs, or and the valves are undercut on the bottom~! I* did not have to do anything~! You wasted your time on those old smog heads...What is your time worth? Like I said to the guy on the other question...You told him to spend all of this BIG MONEY ON CAM, LIFTERS, Valve train components, having the heads sent out to someone you knew~! Like I said before...People get krap feed to them here on this site like you just did to him...I suggested a simple cam Lunati 60101LK cam, a airgap intake, 600cfm carb and unported 305 heads,,,I would prefer 461/462 heads, or these heads, or vortec heads...You see your the screw up by telling him HYD cam are for women and that all of your knowledge is GOD,,,,,Your just like I said, I don't care who you are, what you know and how much your daddy gave you to build what ever...Your the screw up with what you told him to do for the daily driver when gas is over 4.50 a gallon for 93 octane~! Yep, your real, real smart
Fully home port the 416 heads and add new 1.94" intake valves.
When your machinist does the new valve job get him to machine the guide boss shorter for aftermarket seals and increased valve lift.
Don't be shy with the porting Use a felpro 1205 intake gasket as a guide.
Shave the heads down to get the compression ratio up on the 307.
You want a 52-53cc finished chamber volume to get the cr up.
Install with a thin felpro 1094 gasket you want the compression ratio as close to 10.5:1 as possible.
Drill and roll pin the rocker studs. Do this yourself
Isky Z27 solid lifter cam #201027 Isky 235D springs. 1.75" installed height
282-282 247 247 @.050 .507 .507 108LSA .016 .018 lash
104 112 centers degree the cam in
1.5 rockers can be roller or good stamped steel.
Performer RPM manifold 650-750 holley.
4.56 4.88 gears.
9" race converter. 4000++ stall a 5000 stall is not too much
Shift it around 7000 rpm.
you will slay your fair share of 350's and 383's
SO TELL ME, WHO'S YOUR DADDY? I FIGURE HE WOULD HAVE SPENT CLOSE TO 2,500 BUCKS WITH YOUR KRAP STALL CONVERTERS, REAR END GEARS,PORTING, VALVE SPRINGS, LOTS AND LOTS OF MONEY~!....MINE WOULD HAVE COST HIM UNDER $1,000 BUCKS AND IT RUNS ON 89 OCTANE, MAYBE 87OCTANE
Yor Idea Of An Engine Build
CAM, LIFTERS, SPRINGS AND RETAINERS...REAR GEARS, $143.00, STALL CONVERTER, $259.00... NEW VALVES FOR THE HEADS, 64.95 INTAKE, 64.95 EXHAUST.... INTAKE 145.00,....750CFM HOLLEY hp 464.00...THIS DOES NOT INCLUDE THE GASKETS, NOR THE LABOR FOR THE MACHINING OF THE VALVE GUIDES, VALVE JOB, OR DECKING THE HEADS...
MY COSTS FOR MY IDEA...LUNATI 60101LK CAM @188.00.....INTAKE@144.00, QUICK FUEL CARB@299.00 STOCK HEADS WITH VALVE JOB, OR REMAN 461/462 HEADS AVERAGE ABOUT $300....
DOES NOT NEED STALL CONVERTER, NO 93 OCTANE GAS, MAYBE 89 AND WITH WATER METHANOL INJECTION, COULD GET AWAY WITH 87 OCTANE...
MINE IS CHEAPER THAN YOURS AND RUNS DAILY CIRCLES AROUND YOU~! MOST OF ALL IS THE MONEY I SAVED ESPECIALLY AS YOU STOP AT EVERY GAS STATION TO FILLUP~!
P.S. ALL PRICES COME FROM SUMMIT CATALOG AND ARE CURRENT...I TRIED TO DO SUMMIT PARTS TO CUT THE COST OF YOUR IDEA, BUT IT STILL PROVED COSTLY!
ALSO JUST FOR GRINS AND GIGGLES...I WENT TO AUTO MECHANICS SCHOOL IN 1975 AND RAN TWO BUSINESSES UP UNTIL GAS WENT TO $1.00 PER GALLON...THAT IS WHEN A LOT OF MOM AND POP GAS STATIONS WENT OUT OF BUSINESS DUE TO THE BIG BOYS BUYING THEM OUT....SEVERAL YEARS LATER, I GOT A TEXACO GAS STATION AND SAD BUT TRUE, ONLY HAD THAT FOR A LITTLE OVER A YEAR, WHEN THEY WENT BANKRUPT AND SOLD OUT TO SHELL. MINE WAS ON THE INDIAN RESERVATION AND THE LEASE WAS UP AND THEY WANTED THEIR LAND BACK...THAT STATION IS NOW GONE...I HAD A LOT OF FUN WORKING ON CARS OVER THE YEARS AND I CAN SAY THAT TODAY'S CARS ARE EASIER TO WORK ON THAN THE ONES BACK WHEN I HAD BLONDE HAIR...I INVESTED IN A COMPUTER TO DO THE CARS AND THEY TOLD ME WHAT TO CHECK WHEN I HAD THE TEXACO A FEW YEARS AGO...SIMPLE, COMPARED TO HAVING TO REALLY FIGURE OUT DOING IT THE OLD WAY ON THE 70'S AND EARLY 80'S CARS....
AS FAR AS EDUCATION IS CONCERNED, ALL THE BIG BOYS HAVE CONTINUED EDUCATION AT GM, FORD AND CHRYSLER VIA SATELLITE AND YES EVEN THEY READ PERIODICALS MAGAZINES AND GET INFORMATION OFF THE NET, LIKE I DO...EDUCATION NEVER STOPS...IT IS PEOPLE LIKE YOU THAT WHEN YOU GET CRITICIZED THAT BLOW GASKETS AND PROCLAIM THAT THEY HAVE DONE ALL OF THESE THINGS AND THEY ARE GOD...SAD, VERY SAD...THAT IS WHY I WALK QUIETLY AND CARRY A BIG STICK....
I just noticed these were bow tie heads~!
what I just noticed is that my comparison of the heads were the Bow Tie Vortec heads not the 601's that are stockers on L-31 motors~!
So, armed with this information from Chevy Performance Magazine, the Dart/Summit Vortec heads really did OK for not being true vortec designed heads~! At max 5,500 rpm with this particular cam, they were down by 15 hp from the bow tie vortec's Not too shabby~!
average horse power of heads
Here is the optional Scoggin Dickey's Bow Tie Vortec heads, vs the Summit Racing/Dart Vortec replacement heads. This is the average hp over a powerband of 5,700rpm
GM Bow Tie head Summit Racing/Dart vortec
403 tq 293 hp 393 tq 289hp
So, what does this all mean?
GM Bow Tie optional heads produced 10# more average TQ and only 4 more average HP over the Summit/Dart vortec head....Over the stock L-31 heads, the summit heads have the advantage of being a thicker casting head and they come stock with screw in studs and the heads need to use self-aligning rocker arms.
The price difference in the 2 fully assembled heads speak for themselves. Summits with shipping cost me 585.00 out the door. I got them with free shipping~! I will let you compare the price of the OPTIONAL Vortec's from Scoggin Dickey's.....But of course get ready for how much you need to spend to get only a small amount of increase in performance~!
Recently, I found a test from one of the car magazines testing a SBC 305 motor build with a lot of different products used and the consensus is that 305 heads are too fragile with the thin castings that they are. Moreover, is the fact that they did use Procomp's HEI distributor, roller rockers and airgap intake manifold and did several pulls on a dyno,(lots of pulls) which should be proof to some that the parts are adequate and cost effective in a build up.
Here is the cashed article below...Have fun reading it and compare the cams, intakes, rockers and carbs they used and consider the parts selection from companies people have claimed DID NOT work, because of being made in China....Problem is, most any part and products are just that, made in China...Doesn't matter what the name brand is, from American name brands to the Chinese counterparts, few are made in the U.S. anymore...Be loyal to yourself and think for yourself, not what the crowd is currently doing...Walk your own walk....
And most of all, have fun building it~!
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