Need BBC head recommendation
07-12-2004, 07:30 PM
#1
Burning Brakes
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Need BBC head recommendation
OK guys, short of my cam selection i'm looking to pick out my aluminum cylinder heads. I'm installing a 540ci into my C3 (drive train and trans upgraded for torque) which will be primarily street oriented, rare visits to 6000 rpm. Understand traction will be a concern. Since the rpms will be in the 1800 - 4800 range of normal use I could use your input on which heads to get. Trans is a Viper 6-spd with 3:55 rear. What intake port size CCs should I be considering, 310s, 340 or 350? Most likely will use hydraulic roller setup so any thoughts on cam selection would be appreciated. thx.
07-12-2004, 08:50 PM
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I haven't heard much about them on the forum but the machine shop which came well highly reccomended to me was very keen on the Brodix Race Right series heads which are fairly new. I bought a pair (not cheap) and am ready to give the motor a try in a week or so one I obtain the remaining needed fuel system plumbing. I called the manufacturer tech line a couple weeks ago to find out what plugs I should put in them. Ended up speaking to the owner who designed the head with his brother who spoke to me in detail for the better part of 30 minutes about his design. I was really impressed with the guy and hope his product is a reflection of his customer service and pride he has in the manufacturing. I was simply amazed to have spoken to the designer. All that being said, the machine shop still dissambled them in entirety and did some port matching work to them. Hope to be able to have some dyno results to post on the 496 in a few weeks or less.
07-14-2004, 01:49 AM
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Heads
Oh boy...one of my favortite subjects!
First off, forget just about all the *normal* numbers you've seen with regards to port size and airflow. A 540 needs LOTS of airflow. Everything you do to it needs to be aimed at getting air in and out of it. You will need to think larger..don't get hooked on the "smaller is better" routine. It will work, but you will leave so much power on the table it's ridiculous. A 540 will run out of air quickly even with relatively large parts in it.
I spoke with lots of folks before I built mine and found most folks using Dart 320's or Brodix -2's or maybe 2x's. Unless the heads were heavily ported and worked on, HP was typically on the decline after 6200 rpm even with big solid roller cams. Many were literally dropping like a rock after 5500 rpm or so. That may not seem like too much of an issue, but I can tell you the *funest* motor of all to drive is one that makes good power and HOLDS ONTO it after peak HP is reached.
The advent of CNC heads has drastically changed the lanscape. The Dart CNC 335's,the AFR 335's or Brodix M2's have all allowed us to get unreal airflow out of the box. It seems like a huge increase in price, but I can tell you to get a qualified head wizard to perform his magic using a flowbench and meticulously massaging each port and retesting constantly as he goes is much more expensive! You can get 90% of the improvement much easier with CNC stuff.
There are lots of individual preferences out there, but here's my take on it. The Darts are a great head out of the box and a gazzilion folks use them. Many engine shops push them and they get a great price. They make fine power. It's subjective again, but I've had more than one porter complain that they see porosity issues and the stud bosses are weaker. Not an issue for a Hyd roller cam and it's springs, but still an issue. Steve B. (632 C2) made 840+ HP on pump gas with his 540 using essentially out of the box Dart 335's. He did have a vacuum pump system but his cam wasn't crazy by any means relatively speaking. More than you will want, but at least you know heads are capable if you ever want to upgrade.
Brodix until recently didn't really have an out of the box head that would flow with the Darts of equal cc's. But they are considered to be about the strongest casting out there and stud bosses are better. They do not exagerate their flow numbers as many companies do. My heads actually flowed better than advertised after two years of running with the two year old valve job. I was very impressed. The M2 versions are killer.
AFR is the relative newcomer to the big block field. From all indications they may have everyone trumped. They seem to have fantastic quality and strength and their out of the box flow numbers whether CNC or cast are fantastic. Tony Mamo designed them and he has managed great flow with a relatively small port. Their ports tend to favor close to single pattern cams because exhasut flows so well. Mark L (ML67) has a new set of 335's on his revamped 548 in his C-2. He's just getting it running,so we don't have before/after results yet, but I think he is very pleased! He previously ran professionally ported Brodix's. It will be interesting to see how they perform. We're expecting good things.
ProTopline also makes a very nice looking CNC head. There have been lots of discussion about quality of a few cases, but the set I saw were really nice and probably had the prettiest CNC port I've ever seen as far as appearance. They also flowed exactly as advertised on the bench.
Canfields have a strong reputation. They are typically cheaper if you shop around and can make great power. There are CNC versions of them too. They also make the ones Summit sells under their brand name I believe.
The Edelbrock/GM's can make the power as witnessed by the new 572/620 and 572/720's. There are the normal versions and then there are the race versions with huge ports. Two different worlds there. My personal opnion is that these are not a good choice for a 540 if starting from scratch. The heads themselves are fine, but I think the airflow just isn't there to support a big motor. Another Forum member (Vettemaniac) has them on his C-3 (rectangular ports) and has experienced power drop off above 5000 rpm. He is currently reinstalling them after getting them ported along with a new cam to help stretch it out further. The good news is the guides and all have lived well after a few years of literally daily driving them to work and back and no issues with quality have surfaced. Just don't flow enough without work.
The Merlins are a pretty decent head I believe. I've run the iron versions before with great results on my 427, but have no experience directly with the aluminum ones. All their other stuff is great, so I have no reason to expect different from the aluminum heads.
One issue will be the exhaust ports. Many are raised to increase airflow, which can cause issues with headers in some cases. Regular Brodix are up .600", Darts are similar I think maybe a little less, Canfields and AFR's are around .350/.400 or so. Merlins are up there too I think. The Race Rite's are std height as are the Edelbrock GM's. Usually the AFR's seem to do fine, the Canfields do depending on header, the Brodix and Darts will likely require a little work, typically on the left side. Not a deal stopper, but something to be ready for.
All this being said, I picked Brodix for mine and have been very happy. The first version of mine was a TQ monster even though I used a relatively small old style single plane Team G intake, 365 cc Brodix 2Xtra's and a custom solid roller cam 262/273 on 112 LSA with .672/.675 lift. It made 732 hp@ 6200rpm or so with 10.5 compression on pump gas and was just about uncontrollable traction wise. Lots of fun but a real handful. Bad part was it dropped about 140 HP by 7000 rpm. The new version involved serious professional flow bench work, a new ridiculously sized Edelbrock Super Victor intake and a 272/278 on 110 LSA .731/.731 cam. It made 825HP@ 7400 rpm and was still climbing! That's with 11.06 compression on pump gas with no vacuum pump system. Actually much more controllable under power and pulls like an animal up top! I recently stuck a smaller solid flat tappet cam in it to try and the fantastic heads are allowing it to perform much better than I expected!
I know this is more than you wanted to know, but this is how I'd look at it. If you're going to cheek up for CNC work a nice set of AFR 335's, Dart 335's, M2 etc will be great. If you are going to use as cast, I'd use Brodix 340 or 365cc ports, Merlin 350's, Canfield 350's etc. You won't notice any loss of throttle response, trust me. Mine is fantastic even after porting the 365's!! There are a few witnesses to it first hand here on the Forum!
Whatever you do, don't scrimp on airflow. You can use a nice small cam with good heads and it will run well. But if you strangle it with small heads, no matter what cam you install, it will be a slug!
Also think about 3" exhaust.....2.5" will restrict it badly even in the
5500-6000 rpm range.
If using a hyd roller, You are going to want something in the 245-250* range@.050 (seems big...but not bad for a 540) and anywhere in the .600-.650 lift range. Don't go too small. I'd use a 112 LSA most likely to make it nice and smooth with the O/D. You might even step out to a 114, but that would be stretching it. That double O/D is going to make things tough. You may want a little more rear gear.
Hope all this helps!
JIM
First off, forget just about all the *normal* numbers you've seen with regards to port size and airflow. A 540 needs LOTS of airflow. Everything you do to it needs to be aimed at getting air in and out of it. You will need to think larger..don't get hooked on the "smaller is better" routine. It will work, but you will leave so much power on the table it's ridiculous. A 540 will run out of air quickly even with relatively large parts in it.
I spoke with lots of folks before I built mine and found most folks using Dart 320's or Brodix -2's or maybe 2x's. Unless the heads were heavily ported and worked on, HP was typically on the decline after 6200 rpm even with big solid roller cams. Many were literally dropping like a rock after 5500 rpm or so. That may not seem like too much of an issue, but I can tell you the *funest* motor of all to drive is one that makes good power and HOLDS ONTO it after peak HP is reached.
The advent of CNC heads has drastically changed the lanscape. The Dart CNC 335's,the AFR 335's or Brodix M2's have all allowed us to get unreal airflow out of the box. It seems like a huge increase in price, but I can tell you to get a qualified head wizard to perform his magic using a flowbench and meticulously massaging each port and retesting constantly as he goes is much more expensive! You can get 90% of the improvement much easier with CNC stuff.
There are lots of individual preferences out there, but here's my take on it. The Darts are a great head out of the box and a gazzilion folks use them. Many engine shops push them and they get a great price. They make fine power. It's subjective again, but I've had more than one porter complain that they see porosity issues and the stud bosses are weaker. Not an issue for a Hyd roller cam and it's springs, but still an issue. Steve B. (632 C2) made 840+ HP on pump gas with his 540 using essentially out of the box Dart 335's. He did have a vacuum pump system but his cam wasn't crazy by any means relatively speaking. More than you will want, but at least you know heads are capable if you ever want to upgrade.
Brodix until recently didn't really have an out of the box head that would flow with the Darts of equal cc's. But they are considered to be about the strongest casting out there and stud bosses are better. They do not exagerate their flow numbers as many companies do. My heads actually flowed better than advertised after two years of running with the two year old valve job. I was very impressed. The M2 versions are killer.
AFR is the relative newcomer to the big block field. From all indications they may have everyone trumped. They seem to have fantastic quality and strength and their out of the box flow numbers whether CNC or cast are fantastic. Tony Mamo designed them and he has managed great flow with a relatively small port. Their ports tend to favor close to single pattern cams because exhasut flows so well. Mark L (ML67) has a new set of 335's on his revamped 548 in his C-2. He's just getting it running,so we don't have before/after results yet, but I think he is very pleased! He previously ran professionally ported Brodix's. It will be interesting to see how they perform. We're expecting good things.
ProTopline also makes a very nice looking CNC head. There have been lots of discussion about quality of a few cases, but the set I saw were really nice and probably had the prettiest CNC port I've ever seen as far as appearance. They also flowed exactly as advertised on the bench.
Canfields have a strong reputation. They are typically cheaper if you shop around and can make great power. There are CNC versions of them too. They also make the ones Summit sells under their brand name I believe.
The Edelbrock/GM's can make the power as witnessed by the new 572/620 and 572/720's. There are the normal versions and then there are the race versions with huge ports. Two different worlds there. My personal opnion is that these are not a good choice for a 540 if starting from scratch. The heads themselves are fine, but I think the airflow just isn't there to support a big motor. Another Forum member (Vettemaniac) has them on his C-3 (rectangular ports) and has experienced power drop off above 5000 rpm. He is currently reinstalling them after getting them ported along with a new cam to help stretch it out further. The good news is the guides and all have lived well after a few years of literally daily driving them to work and back and no issues with quality have surfaced. Just don't flow enough without work.
The Merlins are a pretty decent head I believe. I've run the iron versions before with great results on my 427, but have no experience directly with the aluminum ones. All their other stuff is great, so I have no reason to expect different from the aluminum heads.
One issue will be the exhaust ports. Many are raised to increase airflow, which can cause issues with headers in some cases. Regular Brodix are up .600", Darts are similar I think maybe a little less, Canfields and AFR's are around .350/.400 or so. Merlins are up there too I think. The Race Rite's are std height as are the Edelbrock GM's. Usually the AFR's seem to do fine, the Canfields do depending on header, the Brodix and Darts will likely require a little work, typically on the left side. Not a deal stopper, but something to be ready for.
All this being said, I picked Brodix for mine and have been very happy. The first version of mine was a TQ monster even though I used a relatively small old style single plane Team G intake, 365 cc Brodix 2Xtra's and a custom solid roller cam 262/273 on 112 LSA with .672/.675 lift. It made 732 hp@ 6200rpm or so with 10.5 compression on pump gas and was just about uncontrollable traction wise. Lots of fun but a real handful. Bad part was it dropped about 140 HP by 7000 rpm. The new version involved serious professional flow bench work, a new ridiculously sized Edelbrock Super Victor intake and a 272/278 on 110 LSA .731/.731 cam. It made 825HP@ 7400 rpm and was still climbing! That's with 11.06 compression on pump gas with no vacuum pump system. Actually much more controllable under power and pulls like an animal up top! I recently stuck a smaller solid flat tappet cam in it to try and the fantastic heads are allowing it to perform much better than I expected!
I know this is more than you wanted to know, but this is how I'd look at it. If you're going to cheek up for CNC work a nice set of AFR 335's, Dart 335's, M2 etc will be great. If you are going to use as cast, I'd use Brodix 340 or 365cc ports, Merlin 350's, Canfield 350's etc. You won't notice any loss of throttle response, trust me. Mine is fantastic even after porting the 365's!! There are a few witnesses to it first hand here on the Forum!
Whatever you do, don't scrimp on airflow. You can use a nice small cam with good heads and it will run well. But if you strangle it with small heads, no matter what cam you install, it will be a slug!
Also think about 3" exhaust.....2.5" will restrict it badly even in the
5500-6000 rpm range.
If using a hyd roller, You are going to want something in the 245-250* range@.050 (seems big...but not bad for a 540) and anywhere in the .600-.650 lift range. Don't go too small. I'd use a 112 LSA most likely to make it nice and smooth with the O/D. You might even step out to a 114, but that would be stretching it. That double O/D is going to make things tough. You may want a little more rear gear.
Hope all this helps!
JIM
07-14-2004, 03:16 AM
#4
Burning Brakes
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Jim, all I can say is thanks. You've provided me with much more than I would have expected. I've been going thru all of those head manuf. and just recently found Canfields and ProTopLine. When I narrow down to a couple of choices I'll probable pester ya again. thx. MIKE
07-14-2004, 12:32 PM
#5
Team Owner
Dart head site
http://www.dartheads.com/cbbhpro1cnc.htm
I'm only a small block person, but I found out early on when I bought my Dart 227 cc pro1 heads for my original 383 that I was amazed at how well they run with relatively mild SR cams.
The head intake port CC is only part of the, "How the motor acts equation." You actually have to look at the total intake port track volume. In the case of a single plane you have massive runners that have to get the colume of air moving when the intake valve opens.
Cam duration which causes overlap reversion is much more detrimental to low rpm performance than an extra 25 cc's of head intake port volume.
I have found Dart to be conservative in what to put on a given motor.
My 227cc CNC's are recommended for race motors of much larger ci
I'm only a small block person, but I found out early on when I bought my Dart 227 cc pro1 heads for my original 383 that I was amazed at how well they run with relatively mild SR cams.
The head intake port CC is only part of the, "How the motor acts equation." You actually have to look at the total intake port track volume. In the case of a single plane you have massive runners that have to get the colume of air moving when the intake valve opens.
Cam duration which causes overlap reversion is much more detrimental to low rpm performance than an extra 25 cc's of head intake port volume.
I have found Dart to be conservative in what to put on a given motor.
My 227cc CNC's are recommended for race motors of much larger ci
07-14-2004, 03:39 PM
#6
Safety Car
As usual, after Jim addresses the issue there is not much left to say. I will add, for the money, the Canfields and Protoplines are hard to beat. The Protoplines have had some quality issues in ther past (due to a now gone owner) and are supposedly ready to get back on track.
The 335 AFR CNC's are a very sweet head for a street 540.
The 335 AFR CNC's are a very sweet head for a street 540.
07-17-2004, 06:12 PM
#7
Burning Brakes
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I would go with the brodix heads.I have had two sets of darts and ripped the stud bosses out of them.My new brodix m24xtra custom cnc heads have proven the very best i have had.They have 370cc runners and got over475cc of flow at .700lift. This head on my new 632 +8 with a single carb1350 nickerson dominator made 970 hp with 8.75compression. Wait til the 14-71 goes back on it.320cc heads and smaller for 500inch motors or less.345 minimum on a 540 as stated above is right.
