I see Bret, and others, saying that they think that the canted valve is one of the best setups. Atleast, by the flow numbers, the Edelbrock BB mopar heads flow almost like the BB ford and BB chevy canted heads that have ports that are almost 100cc smaller! Isnt this a good thing? The same goes for the exhaust side. How come the mopars get the same flow out thier exhaust then the fords and chevys with a smaller port?

Thanks,
Jeremy

 

A lot of port volume has to do with port length, so if you have a shorter port like the Mopar then you will have less volume. It's a shame that they don't tell you the min and average cross sectional area.

The reason Canted Valves are so good is the fact that when the valve opens it deshrouds itself more the farther the valve is open because it's moving away from the cylinder wall.

Let's compare some BBC heads (26 x 4 valve angle) to some similar volume SBC heads. (14 x 4 valve angle)

These charts give us some more numbers for better comparison.

BBC http://www.weldtech.com/graphics/Brodix2BBplus.gif
SBC http://www.weldtech.com/graphics/BrodixCanted.gif

Now that's 323cc BBC head to a 305cc SBC head.

It's not a super good comparison because the SBC heads are some of the best out there and have 10 deg less for the valve angle. A set of AFR BBC heads would have been better, but we don't have all of these numbers in front of us. But here is the flow chart to show the numbers can be better http://www.airflowresearch.com/pages...rted-graph.gif

The flow numbers are both in the high 300's and the SBC head out flows the BBC one. What you want to look at is the min cross sectional area.

2.653 sq in for the SBC head and 3.50 sq in for the BBC, that's a big difference and shows how much the extra 10 degs of valve angle is hurting the BBC port.

In this case the head with the smaller cross sectional area flows more air. Most of this is port shape and design. The Canted Valve Small Block heads are a more modern design and layout than the BBC. Going to a aftermarket BBC head that get's away from the traditional layout of the heads will show you how much you can gain in flow getting away from classic head layouts.

http://www.brodix.com/onlinecatalog/.../page9-10.html

14 x 4 BBC head which is made for BIG MOTORS, but it moves some stupid air.

Same with these heads but to a lesser degree.
http://www.brodix.com/onlinecatalog/...8/page7-8.html

Bret

 

So are you saying that BB Chevy heads have a larger cross sec then BB Mopar or the other?

 

They might and they might not.

The wedge heads were designed for a 383-440 cube motor while the BBC started off at 396-427 and then 454, obviously bigger on both now.

Bret

 

Would it be safe to say then that the Mopars have longer runners, how do the 2 compare? I also hear that the uneven ports on the BBC are a disadvantage. Is this also true, or has this been fix by the aftermarket?

 

Less runner volume and the same cross sectional area means shorter runners.

The BBC is not 100% fixed with aftermarket heads on the left and right side ports. There are things you can do to make up for it though, but it would be better if they were not that way.

Bret

 

Here's a head that's flowing over 400cfm out of the box! And I almost forgot to mention its for a Small Block Chevy! I would say this is the best flowing head on the market today for SBC when it comes to max flow numbers. Plus 11 degree valve angle. Can't get any better then that. WOW!



Dart Small Block Chevy Little Chiefs:

Material: 355T6 alum alloy
Comb Chambers: Sm port – 36cc Lg port – 34cc
Intake Valve Dia: Sm port - 2.180” Lg port – 2.230”
Intake Port volume: 275cc - Small & 315cc - Large
Intake Port Dim: 275cc = 2.200” x 1.310” 315cc = 2.270” x 1.410”
Int Port Location: Raised, 2.000” from deck (asymmetrical)
Intake Gasket: Mr Gasket#
Exh Valve Dia.: 1.550”
Exh Port volume: 111cc
Exhaust Port Dim: 1.740”w x 1.490”h
Exh Port Location: Raised, 2.900” from deck (symmetrical)
Exhaust Gasket: Fel-Pro
Flow, Intake: 275cc = 388 cfm 315cc = 411 cfm @ .900 lift / 28” (Super Flow 1020)
Note: Flow numbers will be 15-20cfm higher on Super Flow 600)
Flow, Exhaust: 276 cfm @ .900 lift / 28”
Fuel Injection: Can be ordered with nozzle bosses
Manifold: Dart Alum , individual runners 4150 or 4500 8 _” tall (std deck)
Milling: Min. cc / (.00 ” = 1cc) Flat mill only.
Pistons: Custom aftermarket pistons.
Push Rod: Clearanced for 3/8 dia.
Retainers: Titanium (10 deg)
Spark Plug: .750” reach, gasketed. Champion C57C / C57YC
Spring Cups: 1.625 x .035
Spring Pockets: 1.740” OD”
Springs: 1.625D w/cup max installed ht = 2.150+ (.950” lift)
Studs, head: Dart#
Valve Angles: Int = 11º x 4º Exh = 6º x 4º
Valve Length: Int – 6.000” Exh – 5.750” .250” tip
Valve Stem Dia: .3110 “ - 5/16”
Valve Train: Jesel with individual stands
Valve Guides: 1/2” OD Mag - bronze Cut for ???.530” PC seals (.002” press)
Valve Guide length: 2.100”
Valve Guide clearance: .0014” - .0020” (with our .3110” dia. valve stem)
Valve Seats: Copper-berylium .006” press
Valve Seat dim. Int. – 2.300” x 2.150” x .400” Exh – 1.650” x 1.400” x .400”
Valve Seat angles: 275cc = 50º 315cc = 55º Ex = 55º
Torque: Head Studs = 70 ft/lb (3/8”= 55 ft/lb); Manifold = 35 ft/lb
Block Use: Any SBC Iron or Aluminum
Weight: 28 lbs

 

When you reference the Mopar heads, are you referring to the Hemi heads?

If so, I would think comparing a cross-flow head would have a **slight** (< ) advantage over anything Chev or Ford could battle with.

I wonder how much more flow a cross-flow chamber design will promote over a closed chamber design (all else being equal)?

The intake charge has a direct shot at the exhaust valve for improved scavenging.

 

that dart head is pretty wild

how much power could that make on a big 427 small block, or maybe world product's crazy 454 short block? 1000hp? that'd be some sb chevy

 

Jimmy17 - I know that the old NHRA chevy prostock trucks used canted valve heads, whether it was the Dart, Brodix, or GM im not sure. I think they are all capable of well over 400cfm. Those guys were making 900 or so on a 358ci motor. Those motors probably turned 10,000+ though. I would say on an all out 454 small block (not the world products shortblock either) you are right at 1000HP if money was no object, and of course an extremely high maint. machine.