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Re: Dart vs AFR heads on HP 500
Originally Posted by KAAMA
I cannot recall the the Crane 731 cam specs, but it might have too long of a intake/exhaust duration split for it to work well with the AFR heads. The head/cam combination have to work together for the engine to produce good results. I'm not saying a 731 cam wont still work, but you might as well retain the stock cast iron GM heads you now have and have some pocket port/bowl work done to them if you are going to keep that cam. With too much of an I/E split on the cam you'd still see some power increases with the AFR's, but without a properly selected cam you will be holding back their potential by not letting them do their job correctly.
Also, anything new would be good idea, although you can probably re-use the rocker arms you now have---just inspect them, but you may need a different length rocker arm stud for the AFR heads. I would highly suggest new springs, retainers, lifters, and pushrods. RMbuilder would be excellent to consult for your cam/valve train and will work with you & your engine builder. Just make sure that whoever is doing the work does the job RIGHT and KNOWS what the heck he is doing...not by his sweet talking words---but by someone who has a lot of experience and a good reputation because there is a lot of $$$ involved and there won't be much room for error. |
Re: Dart vs AFR heads on HP 500
Originally Posted by CONDOR24
...thanks for all your advise,what kind of realistic power difference is there between porting/milling my iron heads and switching to aluminum ones if i choose to keep this cam? whats the best cost effective approach?
I can tell you this....if you currently have the GM rectangle port heads you should be aware that they are prone to cracking inbetween the seats! So, why invest big money in porting the heads when they may end up cracking and have to throw away? Perhaps RMbuilder/Bob can help you with your choices based on how much you're willing to spend. He's very easy to talk to and very honest, and professional. The name of his company is called Marine Kinetics...(585) 654-8583. |
Re: Dart vs AFR heads on HP 500
basing your purchase on flow numbers is useless. Port length, cross section and many other variables is where you need to spend your time looking. I have yet to see a flow bench or a dyno with a prop on it and in the water. I could show you some antique iron heads that flow 330cfm at .600 that are from a small block ford engine, problem is they get very turbulent at around .500, but hey that 330cfm flow figure sure looks great.
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Re: Dart vs AFR heads on HP 500
Kaama I see you are also from michigan, I have contacted Bob and he is cuurently working up an estimate and parts needed to do my upgrade with the AFR 315's and i was wondering if you can guide me to a reputable boat mechanic that can do the upgrape on my motors, as i ssume i will need to pull the motors to do the cams.
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Re: Dart vs AFR heads on HP 500
Originally Posted by laszlo01
Kaama I see you are also from michigan, I have contacted Bob and he is cuurently working up an estimate and parts needed to do my upgrade with the AFR 315's and i was wondering if you can guide me to a reputable boat mechanic that can do the upgrape on my motors, as i ssume i will need to pull the motors to do the cams.
I don't know how soon Dave Wesseldyk would be able to get to you as he is trying to get two Skater's and a Hustler out the door, BUT there is a precision machine shop just down the street from him named Performance Engineering that has a very good reputation when it comes to marine hi-perf engines. The guy (Bill) who assembles the engines has been there for about 15 years and was trained by Dave Wesseldyk when Dave used to work there. They currently do all or most of Dave's block & head machine work there---so they know there stuff and are familiar with the clearances/tolerances it takes for a marine engine to survive. Bob Madara has worked with a customer who took his supercharged engines there last fall for a rebuild and provided cams for his project as Performance Engineering built the engines. They have a nice labor/price sheet (plus directions, phone number, etc) on their website so you know how much it will cost for a specific machining operation, assembly, etc. They're usually pretty slow this time of year...so, I am sure they can probably get to you pretty quickly if you want. Here's their website: www.Pereng.com |
Re: Dart vs AFR heads on HP 500
Originally Posted by KAAMA
(plus directions, phone number, etc) on their website
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Re: Dart vs AFR heads on HP 500
Originally Posted by woody1
basing your purchase on flow numbers is useless. Port length, cross section and many other variables is where you need to spend your time looking. I have yet to see a flow bench or a dyno with a prop on it and in the water.
This is where your Profeesional head porters come into play. They can give you more information then your brain can digest for a while. :D The AFR heads are very modern and top of the line for 'out of the box' stuff. Just keep the sizes in check - again talking to a Pro head porter, AFR themselves, or a WD/retailer that knows/breathes/lives what they are doing. Speaking of cross section - I, for one, cannot wait until the AFR Oval port and Oval Port CNC heads come out and people start to use them on our normal 454-509 (or so)cid marine motors. Hopefully soon, real soon. Let's cross our fingers. Drool, drool. :D |
Re: Dart vs AFR heads on HP 500
Sorry to keep replying (in a row) but I truly love this medium pocket $$$ stuff. It is what get's me up in the morning.
These don't get advertised much so I like to mention them. http://www.bmfracing.com/bbc_flow_310.htm Yes, flow #'s are big. Okay, huge. No, we shouldn't think this is marketing and the heads are being sold off of flow #'s only. These heads have huge air speed (velocity) thru a relatively small port and make killer + responsive power. Then again, this is Carl Foltz we are talking about, so we know it's good stuff. |
Re: Dart vs AFR heads on HP 500
Originally Posted by woody1
basing your purchase on flow numbers is useless. Port length, cross section and many other variables is where you need to spend your time looking. I have yet to see a flow bench or a dyno with a prop on it and in the water.
Also, I DID mention the experience I had a few weeks ago in my first post...Post #3 on Page #1 about running into a friend of mine with the same boat/hull/length. Now, weather his 556cid engines actually made the 810hp on the dyno sheets I saw is/could be speculation. Do they really make 810hp??? Are they tired and in need of new rings, etc??? Would different props work better for him (he's already tried several)? I can't truly answer these questions accurately....BUT I guess I just didn't expected him to "spank" me.....truthfully, I expected him to RIP MY LUNGS OUT!!! Hey....it's just a hobby and I am just a weekend warrior with my boat....so, I guess I should be at least pleased with my set-up and my "tiny AFR 315's that are way too small for my 565cid inchers that don't/won't make any power"......and that would also include the little cams I have in them. Anyway, I still think you brought up a valid point. |
Re: Dart vs AFR heads on HP 500
Not directed at anyone in particular, people just get caught up in flow numbers really easily. I cant comment on your buddy and your boats as Im a total hack when it comes to marine, we run 600-800 inch IHRA pro stock motors and dabble heavily in small block ford racing. I just see numbers get thrown around far too often. Come and play with some ford hemi head cylinder numbers from an 815 inch kaase motor, then I get excited :D Both the dart and afr head have been proven to be great quality, on the flipside, couple them with the wrong cam and valvetrain and they will end up looking like dogs. Lot more to it then heads. Carry on
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Re: Dart vs AFR heads on HP 500
My BBC guru tells me its a toss up between AFR's and Canfields for 502's and up. His opinion is all the others are a cut below those two.
If looking for a simple 500hp 454, then the Edelbrocks are a good economical choice. |
Re: Dart vs AFR heads on HP 500
Originally Posted by woody1
Both the dart and afr head have been proven to be great quality, on the flipside, couple them with the wrong cam and valvetrain and they will end up looking like dogs. Lot more to it then heads. Carry on
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Re: Dart vs AFR heads on HP 500
This is great news for me. Jim V is actually working on a set of AFR 345 ("as cast") as we speak. He is going to flow them before and after and I'll post the numbers once I get them.
It is correct that all of the exhaust ports are the same for the 305, 325 and 345 "as cast" heads as well as the 315, 335 and 357 CNCed heads. However, AFR installs a tuliped exh. valve in the exhaust for the two larger heads in both series, which increases the flow. Apparently, AFR has determined that the exh. vs. int. flow ratio would be too high with the tulip valves in the 305 and 315 heads (like above 80%). Another thing to note is that at least the 345 "as cast" head (I'm not sure about the 305 and 325) has CNC work in the bowls, and this probably contributes to the seemingly high "out of the box" flow figures that we see on the AFRs. |
Re: Dart vs AFR heads on HP 500
Originally Posted by KAAMA
Well said---just tossing in a cam such as a Crane "741" or "731", etc, in these engines with late design aftermarket heads such as with AFR heads isn't the simple answer anymore these days.
If you would like me to supply the GPS speedo results and RPM range, I would be happy to do so. But, 1999 353 Formula Fastech, loaded (9500 lbs) that went from a 78 mile an hour boat to a 87 mile an hour boat! That's it. Proven! Dave |
Re: Dart vs AFR heads on HP 500
How many people here have cams custom ground? And Im not talking about calling a 9 dollar an hour comp cams hotline tech that picks blindly from the catalog? I bet the truthful answer is very, very few
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Re: Dart vs AFR heads on HP 500
Originally Posted by axapowell
I'm going to have to disagree with your last statement. Gen VI 502, stock HP 500, 800 holley carb, Dart 6200 intake, HVH 1" super suckerspacer, CMI elbow tops, AFR 315 (CNC'd 305's), Crane 168741, Crane extended body roller lifters (dog bone style), Crane ignition (HI-6M and coil), 1.7 ratio rockers on the exhaust, 1.8 ratio on the intake, stock JE pistons, stock rods, and the stock steel crank. PROVEN combo 625HP.
If you would like me to supply the GPS speedo results and RPM range, I would be happy to do so. But, 1999 353 Formula Fastech, loaded (9500 lbs) that went from a 78 mile an hour boat to a 87 mile an hour boat! That's it. Proven! Dave I am actually using a cam that is smaller in .050" duration numbers with a closer I/E split than the Crane 741 in my 565cid engines---but then .050" duration numbers don't alwyas mean anything either. |
Re: Dart vs AFR heads on HP 500
Results aren't near as bad when not correctly specing a camshaft with a high quality designed head than err on a camshaft for a low tech big port (OEM GM) cyl head.
A large lazy port is a disaster waiting to happen. Let's also not forget that the combustion chamber has a lot to do with a cyl heads performance to. Modern combustion chambers are getting much, much better. I have a good head thinking question : is the 'bad' port in a BBC head really the actual bad port. :D |
Re: Dart vs AFR heads on HP 500
Originally Posted by HARDCORE A/O
This is great news for me. Jim V is actually working on a set of AFR 345 ("as cast") as we speak. He is going to flow them before and after and I'll post the numbers once I get them.
It is correct that all of the exhaust ports are the same for the 305, 325 and 345 "as cast" heads as well as the 315, 335 and 357 CNCed heads. However, AFR installs a tuliped exh. valve in the exhaust for the two larger heads in both series, which increases the flow. Apparently, AFR has determined that the exh. vs. int. flow ratio would be too high with the tulip valves in the 305 and 315 heads (like above 80%). Another thing to note is that at least the 345 "as cast" head (I'm not sure about the 305 and 325) has CNC work in the bowls, and this probably contributes to the seemingly high "out of the box" flow figures that we see on the AFRs. Chamber: 124cc/121cc/119cc/114cc flat mill/102cc angle mill Port: 305 cast /315 CNC 325 cast /335 CNC 345 cast /357 CNC The program accounts for the 10/12 cc increase in port size Finish: As Cast: As cast intake/exhaust/combustion chamber. This head receives (standard) a CNC bowl finish program that extends approx 2" below the seat/throat. CNC Chamber: The 2" seat/throat with a complete CNC chamber program. This greatly assists in torque production due to chamber efficiency, which is not necessarily reflected in raw flow numbers. CNC Port: Full Port/Chamber program. Valve selection: (tulip proprietary to AFR) 305/315/325/335- Standard Valves: 7630- 1 Piece SS 1.880", 11/32", chrome stem, +. 100" Nail Head HF #F801259 345/357- Tulip Valves: 7631- 1 Piece SS 1.880", 11/32", chrome stem, Tulip HF # 1297 Optional Valve: 7633- 1.880" Tulip Inconel HF #F 802297 The tulip/tulip Inconel valve does significantly elevate the flow level of the exhaust port. Why the nail head valve standard in the 305/315, 325/335 heads and the tulip in the 345/357 versions? Very often these smaller port heads are improperly cammed (N/A applications) in relation to the Intake/Exhaust bias (80%+). Due to the fact that the 305/315/325/335 versions are most often utilized in moderate RPM/Displacement (under 600 CID/7000 RPM/NA) combinations, flow potential is not necessarily optimized to minimize the effects of excessive exhaust duration bias. Simply put, if you miss on the exhaust duration it's not as detrimental to TQ production with the nailhead. AFR does, however, always recommend the tulip up valve in "a properly cammed application" regardless of the mechanical parameters. The tulip is standard in the 345/357 CNC due to the fact they are properly used in very large displacement/RPM combinations as they are less sensitive to over exhausting via the volume of exhaust gas present and the RPM/time available to evacuate the spent charge. Looking at an engine as an integrated system it makes sense that whenever you make significant progress in any area/areas it becomes necessary to re-evaluate the collateral components, including the camshaft. Bob |
Re: Dart vs AFR heads on HP 500
Originally Posted by woody1
How many people here have cams custom ground? And Im not talking about calling a 9 dollar an hour comp cams hotline tech that picks blindly from the catalog? I bet the truthful answer is very, very few
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Re: Dart vs AFR heads on HP 500
Cstraub - yes they do. :D
Bob - great information and a great example for my thread : http://www.offshoreonly.com/forums/s...d.php?t=137657 that not so many people have seen interest in for some reason. I would think some or many would - but I guess throwing in a cam that 'looks good' is fine for most. I personally like to experiment but heh, that's me....the crack pot. :eek: |
Re: Dart vs AFR heads on HP 500
Originally Posted by KAAMA
Guess I can't argue too hard with you on that Dave! I wonder what the same engine would do with a cam where the I/E split is closer together on the same dyno...either way those are very good numbers and nice pick up in speed for a shelf cam. Guess I'll have to eat my words and sweat this one out! :D
I was going to try my idea and see how the motor performed with an off the shelf cam. I'm not complaining! :D As far as dyno tuning....That has been argued many, many times too. The real dyno is on the boat and in the water. Dyno's are are great asset for break in and base line tuning. That's what they should be used for! I had my first motor on the dyno for a month trying different exhaust, rockers, and carb spacers untill I got the combo right! I didn't believe the numbers untill I drove the boat! Dave |
Re: Dart vs AFR heads on HP 500
Originally Posted by axapowell
Don't get me wrong...I think that if you were to try to squeeze out every ounce of horsepower, then a custom cam is for you!
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Re: Dart vs AFR heads on HP 500
Hey KAAMA,
Speaking of the Hustler at Dave's shop how's that project look :D :D Just anxiously waiting :p |
Re: Dart vs AFR heads on HP 500
Glenn---Lookin' real good...the hard part is over so, you're on the down hill slide for sure! Last I knew/saw Dave has both long blocks assembled....just needs to bolt on intakes, carbs, distributors, and externals and they'll be ready to be dyno'd. Heck, I'm anxious to see for ma own durn self what they're going to do! :D
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Re: Dart vs AFR heads on HP 500
Originally Posted by woody1
Not to mention a much better steel cam core than the usual sadi cores.
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Re: Dart vs AFR heads on HP 500
1 Attachment(s)
As promised, here are the flow measurements that Jim V. did on my AFR 345 as cast heads:
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Re: Dart vs AFR heads on HP 500
Please note that the numbers for the out of the box "as cast" heads are pretty far off what AFR advertises. I asked Jim V. about it and he said that is normally what he sees, even with their CNC heads. He apparently has had discussions with them in the past about this and they claim it's how they do it - the size of the test bore, how you hold the pipe, etc... Sounds like B.S. on AFR's part to me. They're still pretty good flowing heads though.
Check out Jim V.'s ported figures, though. In fact, the best Intake port flows 411cfm @ .800" lift and the best Exhaust 350 cfm @.800" w/ the pipe. I can't wait to stick these suckers on my 540 bottom end and put about 10lbs of boost through them! |
Re: Dart vs AFR heads on HP 500
Afr's numbers are right on for the intakes on my 335 cnc's. The exhausts are close but they are using a pipe, which they don't point out. With porting they will match the exhaust numbers without the pipe. The .600 lift numbers are the best I've seen for any conventional head.
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Re: Dart vs AFR heads on HP 500
I have 357 magnum AFR heads on my 588 Procharged motor and in the same 26' Daytona they are much stronger than the previous heads I have run. Unfortunately I have no dyno numbers for this particular combination. We flowed these heads against a set of 355 Darts's and actually the Darts were 4 cfm stronger at .700 lift, on the same bench. Both exhausts were very close at .700. I will point out that the AFR heads were a little stronger at .500, .600, .650, on the intake side. Overall they were very close. I would say that given the quality of both CNC heads, go with the best deal.
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Re: Dart vs AFR heads on HP 500
Carl Foltz's Bad Mutha' Fuggers.....I mean BMF's. :D On the convential head topic.
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Re: Dart vs AFR heads on HP 500
Originally Posted by jspeeddemon
I have 357 magnum AFR heads...We flowed these heads against a set of 355 Darts's and actually the Darts were 4 cfm stronger at .700 lift, on the same bench. Both exhausts were very close at .700. I will point out that the AFR heads were a little stronger at .500, .600, .650, on the intake side. Overall they were very close. I would say that given the quality of both CNC heads, go with the best deal.
Probably the main reason I chose the AFR's is because of their low lift flow numbers up to .600" lift....especially with the smaller 2.25" intake valve on their 315cc head. My friend with the same boat as mine (32' Active Thunder) who has supercharged 556cid engines just shakes his head in comparison of how well mine runs compared to his. And I am right there at his side from 3000rpm up to the top! Not too bad from a little 315cc head on a big ol' 565cid naturally aspirated engine with a little hydraulic roller cam that idles at 600rpm in neutral. I'm really starting to have a lot fun with it! :) |
Re: Dart vs AFR heads on HP 500
I have always been partial to AFR because they seem to make the most power on any given combination, so it's good to hear that their numbers on the CNC heads are close to their published figures. I guess flowbenches are like dynos, every one gives a little different reading?
Jspeeddemon: How fast does that 26' Daytona run with that combo? Must be a beast! |
Re: Dart vs AFR heads on HP 500
Fantastic thread.......
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Re: Dart vs AFR heads on HP 500
would this work on 500efi's as well...heads, cam and a computer remap ?
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Re: Dart vs AFR heads on HP 500
1 Attachment(s)
Here is some more Jim Valako work. This hand port head was used going to be used as the basis for developing a marketable CNC cast iron head. At the end, we scrapped the project as we didn't see the commercial value.
At this point, Jim then hand ported a set (second set being completed now) based around be best ports on the head we used for the port development. Jim's results were confirmed at Flowmotion, TX. The final ports we picked are highlighted. These heads supported 800+ HP with 505 CID at Keith Eickert's. Not bad for cast iron! Want a set? Call Jim V. |
Re: Dart vs AFR heads on HP 500
BenPerfected -
Wow !!!! :D |
Re: Dart vs AFR heads on HP 500
Good info here
What intakes are you using with the AFR's? Mark |
Re: Dart vs AFR heads on HP 500
Mark, There are a few different intakes that would probably work well, but I am using the Dart single plane intake with 4150 carb base, but I believe they can be had in the 4500 Dominator base as well.
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Re: Dart vs AFR heads on HP 500
Mark did you port match the intake to the heads?
Thanks Mark |
Re: Dart vs AFR heads on HP 500
Originally Posted by woody1
How many people here have cams custom ground? And Im not talking about calling a 9 dollar an hour comp cams hotline tech that picks blindly from the catalog? I bet the truthful answer is very, very few
As I said, this is not a slam against any engine builders here on OSO. The engine builders on OSO now have been here a very long time and have excellent reputations. |
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