Dart Pro 1 head thickness (FYI)
 

Kaama started a thread entitled "head size for a 598 engine". In that thread I mentioned that I was building a 598 with a stage 4 Pro Charger, using the Dart Pro 1 CNC 355 head.

A couple of guys made the statement that those heads have a thin deck surface and are not a good choice for a blower app.

Well, I just got off the phone with the tech dept. at Dart. The average deck thickness on those heads are "about .680", his exact words.
I dont know what you guys think, but, I would tend to think that .680 is plenty.

Just a little FYI
DAVE

I spoke to Dean Nickerson a couple of weeks ago inquiring about a 1000HP blower motor and where to start. I figured he would suggest some heads other than my 325 Pro 1. He suggested going 572" and said the Pro 1 heads (with some opening up) are just fine to use in this application. If you were starting from ground zero, they may not be the BEST choice, but if you already have them they will work great. I have used some of Nickerson's products and trust his opinion. Plus he is a dealer for numerous heads and would not pass up an opportunity to further explain the weaknesses of the Pro 1 if they were truly not up to the task.
Hope this helps!!

So is that from .500" to .750" and averages about .670"??

DAVE YOU REALLY DIDN'T THINK DART WOULD SAY THEIR HEADS HAD PROBLEMS ,,WELL ENOUGH ABOUT THAT

EVEN THE AIR-FLOW IS MIN. 750. PERIOD

PICK UP A BRODIX AND A DART THE BRODIX AND AIR FLO WEIGHT MORE WHY?? YOU WOULD THROW THE DART DOWN IT WOULD NOT EVEN MAKE A GOOD ANCHOR

I HAVE 2 OF DEANS BLOWER MOTORS IN MY SHOP TO FRESHEN UP AND THEY ARE NICE BUT NO PRO-ONES ON THEM VETTE HE'S
A GOOD GUY AND AS YOU SAID TRYING TO SAVE YOU MONEY

BUY WHAT YOU WANT WE WERE JUST PUTTING OUT FACT SINCE WE'VE SEENTONS OF ALL AND MOST HAVE TRULY NOT AND JUST HAVE OPINONS WHICH WE ALL KNOW WHAT THERE LIKE

GOOD LUCK PHONING AROUND ,YOU'LL GET A GOOD SALESMAN :D :D

Bobby, what are some of the problems you have had as far as failures caused by the lack of thickness with the Pro 1's? Just curious as I am sure many other members are. Thanks, Craig

Pro 1's
 

I have been head shoping myself and two very well know shops said the Pro 1 is a pretty good flowing head and would work fine ......with closed cooling. With fresh water cooling both suggested either steel or 320/360 or Brodix or Canfield.

Under thread "Whipple Users" Dustin Whipple strongly suggests the use of Dart Pro one heads, specifically the 335 for the Whipple product. Would the brodix or some other head be a better choice.

HEY GUYS ALL I'M TRYING TO DO IS SAVE TROUBLE FOR GUYS WITH BLOWN BOATS OR BOATS THAT ARE RUN VERY HARD AND MAY BUILD HEAT IN HEADS

CRAIG THE PRO-1'S REALLY ARE GREAT FLOWING H.P.MAKING HEADS BUT FOR OUR OR MOST BOATING APPS. THEY ARE TO THIN AND THE DECK WILL WARP UNDER BOOST AND HEATING SITUATIONS I'VE GOT 4 NOW IN THE SHOP THAT HAVE DONE THIS
BOBS THREAD IS GOOD IN ONE WAY THERE IS NOT ENOUGHT MATERIAL IN THE HED TO LAST WITH SALT WATER
THIS IS ALL MY EXPERANCE !

AIR-FLOW HAS THE BEST FLOWING HEAD YOU CAN BUY OUT OF THE BOX PERIOD LOOK AT THEIR PAGE AND COMPARE EXHAUST NUMBERSTHIS IS CRITIAL WITH A BLOWER AS THE BLOWER WILL GET IT IN

THE BRODIX AND AIR-FLOW WEIGHT A BUNCH MORE THIS TELLS YOU ITS TOUGHER AND MOR RIDGED
I'VE FLOWED ALOT OF HEADS AND FLOW IS IMPORTANT BUT IT HAS TO HOLD UP IN ANBOAT

BB-2XRA AND AIR-FLOW ARE GREAT FLOWING TOUGH HEADS
DUSTIN IS VERY SMART ANHE 'S RIGHT THE PRO-1 FLOWS BUT THE AIR FLOW IS TONS BETTER ALL AROUND AND THE BB2XTRA IS NEXT

HOPE THIS HELPS ! I'LL PRICE ANY HEAD FOR YOU AND SAVE YOU MONEY BUT I DON'T WON'T PROBLEMS LATER

MY 1 WORTH

Bobby, I highly respect your opinions, but has your shop ever put an AFR head on the flow bench and done any comparisons with Brodix, Dart, etc. I mean, everyone who manufactures heads likes to advertise good numbers in the magazines and on their websites, but how much of that is a bunch of ear bending crap? For instance; how much does AFR's 335cc CNC'd head compare to the Dart Pro-1 335cc CNC'd head???? Who's head's flow better OUT OF THE BOX in the CNC'd 355-360 catagory----Dart, Brodix, AFR, Pro-Topline, Canfield??? I already know that the more meat a head has that the more you can port it and shape it----but I want to know what OUT OF THE BOX CNC'd numbers for these big hot dog head manufactures REALLY show on a flow bench and what kind of power they make on the dyno with all else being equal. I want to hear who is TRUELY the king of the hill. I'd like to know the REAL scoop on all these advertised head flow numbers with their CNC's heads. I don't know if you have that kind of info avialable Bobby, but it would sure be nice to know. Thanks.

Mark/KAAMA

I think you'll find most of the above mentioned heads are within 5-10 hp of each other. If you're serious about making power do what the big boys do...PONTIACS.....;) :D Get out the checkbook if you want to "boat" in those waters:rolleyes:

MARK AS YOU KNOW I'VE DONE TONS OF BRODIX AND WE'VE LATELY DONE 2 SETS OF 335 AIR-FLOWS AND THE NUMBERS ON THE EXHAUST ARE TRULY UNREAL THIS IS THE FIRST DIFFERENCE
IN HEADS AS UNTIL NOW I THINK MOST WERE INTERESTED IN
INTAKE NUMBERS AS JDNCA SAID MOST ARE CLOSE TO EACH OTHER .

PONTIAC HEADS STILL RULE TRUE !!!

CNC HEADS COME NOT TO BE MODIFIED ANYMORE THE THICKNESS IS FOR STRENGHT AND REGIDITY !!
THERE AS I'VE SAID ABOVE THEIR IS ALOT OF DIFFERENCE ,JUST PICK UP SOME DIFFERENT HEADS
1 CENT WORTH

MARK THE TOP HEAD COMPANYS HEADS ARE VERY CLOSE TO WHAT THEY ADV. ,,REALLY ,BUT ITS THE WHOLE PACKAGE YOU'VE GOT TO USE THE FLOW THIS IS THE IMPORTANT PART SEE YA

Thanks Bobby...
 

Thanks for your response---sounds like you've got the "hook up" down there! :)

Mark/KAAMA

KAAMA..Chevy High Performance mag did a comparison on 16 different cylinder heads. The AFR 315 cc out flowed alot of major head makers. The comparison was done about a year ago. It is available at www.chevyhiperformance.com makes for some interesting reading. Am in the same boat as everyone else. Going to Aluminium heads and asking the same questions. 540 ci with whipples, AFR suggested using the 315 cc intake runner. Dustin says go with Dart 335. Dustin knows his product for sure and has tested this combination. Not questioning his opinion just asking questions.

BEAK BOATER DUSTIN HAS TESTED THE DARTS AND IT MAY BE A VENDOR OR SPECIAL SUPPLIIER TO HIM ! THE AIR FLOW 315 AS YOU SAID IS A KILLER HEAD ITS EXHAUST NUMBERS BLOW AWAY
THE DARTS AND IS A MUCH STRONGER HEAD THE 335 AFR ARE THE ONES I 'VE RUN ON 540'S WITH WHIPPLES 3.0 LITERS AND 10 TO 14 71'S THEY WILL DISTROY THE DARTS AND LIVE FOR EVER.
THE BLOWER WILL HANDLE AND DOES BETTER WITH SLIGHTLY SMALLER INTAKES BUT THE EXHAUST NEEDS CAM DURATION AND GREAT FLOW ALL THE WAY OUT THE PIPES ,ITS BEEN PROVEN OVER AND OVER AT LAKES ALL OVER ,
JUST WATCH WHAT MAN. TELL YOU THEY MAY HAVE HIDDEN ADJENTAS
DUSTIN I SAY AGAIN IS GOOD THOUGH :D :D
LET ME KNOW IF YOU NEED ANY HEADS ,JUST PM ME THANKS
MY 2 CENTS WORTH :p

KAAMA, I spoke with a rep in the Dart booth last weekend at the PRI show and he claimed the 335 or 355 CNC heads would be worth 50 to 70 more HP over my fully ported 325's on my 13:1 comp 496. He also said the Dart 320's would need to be fully ported to match the flow of the 325 Pro 1 heads in "out of the box" form. I have been reading some of your posts and thought you may be interested in that info. Personally I think he was trying to be a better salesman than he really was.:p We stopped at the Sonnys booth and this salesman (very knowledgeable) made claims that JDNCA1 would pick up 100 to 150 HP by going to Pontiac heads on his dyno confirmed 900 HP pump gas naturally aspirated 632. The total cost for that upgrade would be in the $9000 to $10,000 range. :eek: To bad these HP claims by salesmen aren't backed by a money back guarantee.:rolleyes: If they did I would buy some 335 Pro 1's tomorrow!!:D

Question.......not to change the topic, but lately, I have seen the new Canfield Big Block Chevy 350 cc heads being mentioned quite a bit in a lot of hot rod, and drag racing articles. Has anyone had any expereince with these yet ?

Canfield has always advertised some pretty big flow numbers in the past. I run 2 sets on my sbc's, and I have to admit, for an out of the box head, they really seemed to have a fairly smooth casting quality, consistent raddi in the runners, etc and everything looked nice (I know, looks aren't everything), but I was just wondering if anyone had any experience with the new 350 cc heads ?

"HORSEPOWER HERE----COME GET YOUR HORSEPOWER HERE......"
 

You have to sometimes wonder when an engine builder or a business who sells horsepower parts uses a certain brand of head just because they get it cheaper from a supplier or from the factory. When the only real reason they buy these heads is because they get a good deal on them and for some reason they are buddies with a supplier or something and can buy them cheaper than other brands of heads-----NOT because they flow better than another brand or design of heads, but because they can make MORE MONEY on the heads. That's why I don't always take an engine builder's or parts saleman's word about a certain brand of head they use. Although this may not always be the case, I'm more apt to listen a little closer to an engine builder or horsepower salesman who (for exapmle) says something like this;----

"We use the Dart head for this application and we use the Broxdix for other certain types of applications and we like using the AFR heads for this supercharged application and here's why........"

OR---

"Until we find another brand makes more power, we only use "X Brand" because we have dyno'd it on several different applications and have compared it with all the other top brands of heads and here's why............"

When a person can tell me that he uses different heads for different apps, it tells me he's not "drinking buddies" (so to speak) with any one supplier or manufacturer. But rather he's constantly trying out and dynoing heads to see who's got the BADEST HEAD for a certain type of application. In other words he's looking to give his customers the best product for the application he needs it for---not just the salesman's pocket book. I know it's impossible to try every head and combination, but they can still take some of the top competing head manufactures and dyno test them. Of course I am talking about heads that you take right out of the box from straight untouched castings to CNC ported heads with both of these types of designs only requiring maybe a slight bowl blending, but NO PORTING (such as on straight untouched castings) or any FURTHER PORTING (such as on factory ported heads CNC'd) so as to keep the costs to a minimum.

Any engine builder or someone who sells horsepower products has his own reasons as to why he uses what he uses. And for the average everyday guy who wants to go a little faster, those reasons may be good enough for him and he takes the seller at his word, and that's fine. But there are some of us who want to know a little more of the WHY's, WHEN's, WHAT FOR's and HOW COME's and all the other reasonings behind what the seller is saying to sell his product.

But as Jdnca1 has stated that they all probably flow within 5-10hp of each other. Anything less than that is probably trying to split hairs which can put my above arguements in vain.

As far as hand porting goes that is a totally different subject---someone who does hand porting as a profession is usually able to shape and design a port the way he wants---and even HE has his own reasons as to why he likes a certain brand of casting to accomplish this. However, in this post/arguement, I am talking more about the "out of the box" heads that are available and ready to pretty much bolt right on.

Those Pontiac heads had UNBELIEVABLE flow numbers.....close to 520cfm @.750 lift on the intake. Craig is right about the Sonnys rep, he didn't even hesitate on the 150HP increase claim by going to Pontiacs. I believe him because I've seen it in tests, problem is you need to change a lot to switch and stay on pump gas. The next motor might just have to be a 12.5:1 with a set of pontiacs on it. I think I could leave the flat tops in and just change heads and be close to that CR. Should be good for 1250+hp. I was just looking at some of the materials on those heads, 2.52" intake valves:eek: :eek: 80CC chambers

I ran 14 degree big chiefs for three years. Great head, super flow and pretty good hp. They are not real "pleasure use" friendly. Valves are long (6.7"), I ran titantiums on intakes and an inconel exh.. Pushrods are almost 11" long. Due to the weight and the fact the heads like big lift and rpm spring pressures are higher than normal. Rocker arms need to be gone thru about every 100 hours. Lifters are offset, which promotes their wear rate. Combined with vavle train weight, spring pressures and side load, lifter life is compromised. Cam lobe seems to wear more agressively also. Heads are very tall, probably an inch or so more than the others, creates space problem on side by side installations. Bottom line, they make hp but are probably better suited to a race application. Recently sold mine and will be happy to try something different!

Thanks for sharing your real world experience Bob. My big question has always been how hard do you have to turn it to see the benefits of those heads. I turn about 6500 Max natural and I'm not sure those heads really start working until at least that rpm and probably more like 7200+. To get the potential out of a 632 at 12.5:1 with big chiefs you would likly have to run a cam that was just too nasty to be compatabe with a Bravo. I'm @ 280/288 (running 2 degrees retarded) now and it wants more cam @10.5:1. Coupled with Dominators on a sheet metal intake I'm not sure anyone could make the motor idle (below 1400) with the 300+ durations that would likely be needed.

Hey.. keep this one going.. I am looking at new heads too!! What can one buy out of the box, so you dont have to deal with people! Sell me a head that works in a box and I will buy it! I am interested in experience with the Big Chief heads.. would love to make some serious power with my 565" motor. But dont want a drag race motor..
Thanks
Dick

Mr. Gadgets/
If your looking for some 14 degree or 18 degree Big Chiefs, give Tom a call down at Champion in Palm Coast, FL 386-446-4488. He has a couple pair for sale. One set KE owns and are basically new.

I'll stick with my Merlin's. A friend of my had the Dart's and cracked one after about 50 hrs. Made the motor a milk shake and had to be torn down. When he contacted Dart they said they were having problems with the heads on marine applications. so he went out and got the Merlins and the motors have been running well ever since.

the Dart's are definetely lighter, and you could tell that the merlin's had much more meat on them.

Just one of my experiences with the Dart's.

Mr. Gadgets,

I had experience with the Big Chiefs once before. I worked on a boat about 5 yrs ago that was running the Big Chiefs. Made a sh%& load of power. the problems started when it dropped a valve twice. i was told this is common on a Big Chief in a marine application. the motors were 598's and made about 850hp, not too shabby. Other than dropping two valves they made ton's of power.

Mr Gadgets, from what the gentleman in the Sonnys booth told us you are probably looking at a realistic cost of about $8000 to $10,000 dollars to convert to Pontiac heads. The particular heads he showed us had 80 CC combustion chambers which would mean most pleasure boaters would need new pistons to keep the compression in pump gas regions. That along with a completely new solid roller valvetrain and offset Jesel type rockers it gets pretty salty pretty quick. Another thing to ponder about these type of heads is they start really shining in the 6000 to 6500 RPM and up range. Most Bravo guys just don't like this much RPM nor do they like the lopey idle produced by the cam it takes to get there. I may be wrong, but I feel the Pontiacs will only provide minimal gains in the 5500 to 6000 RPM range over a good set of fully ported Darts or Brodix standard type heads. Hey Gadgets, I think you should do it and give us some real first hand experienced answers to how they work.:p Does anyone remember the class 1 Mercruiser race motor from a few years ago? It had around 12.5:1 compression with solid valvetrain and custom big chiefs. I think the motor was 498" and made 900 HP an something like 6800 RPM. I need that motor for the WETTE VETTE!!!:D It was only available with the #6 I believe.

Wette Vette/

I have some ex-class 1's. The 14 deg Big Chief does take it's own piston, I was running a 9:1 and just tried to put a steel merlin on to see what kind of valve clearance i would have with the chief piston. I could probably get it to work but the valve on a normal Chev head really doesn't work with a Big Chief piston and vise versa. These heads are the ticket for big cubes and especially with a blower!

I don't sale heads, I'm not even a dealer with Dart, AFR, Brodix, Canfield, or any others.
Dustin