Good info on Vortec castings Larry.

Thanks,

Bret

 

A couple question regarding SBC heads:

I was under the impression that the SB2.2 was the "best" head GM had for the small block. But a little research shows that the canted valve heads have more power potential. Why? I had the opportunity last saturday to look at an SB2.2 cutaway engine at the charlotte race in one of the GM displays and was bewildered at the design. The ports are quite long and straight all the way to the valve... seems like the perfect design from what little experience i have... 11* valve angle with a 4* (i think) cant on the intake. Can't remember the exhaust specs. I've never seen the canted valve heads in person, only pictures and descriptions. What is it exactly that makes the canted valve heads "better"? Are there any similarities between the SB2.2 and the canted valve heads?

If either of these heads were to be used on top of a Dart/WP 427 or 434 shortblock, would it be possible to make it "streetable"? Say, a decent idle at around 1K rpm, make peak power around 6500rpm, all with a HR cam (if possible) and maybe 11-12:1 CR? (it's an idea i've been throwing around for a NA project for the Z28) And what kind of power would we be talking here? 700? pump gas?

 

The SB2 has a direct "line of sight" path to the intake valve,and the cant lessens the valve shrouding,by opening the valve to the center of the bore.
It's a bit of overkill for a street engine but it sure would be a conversion piece. It would be very doable and the cam will determin the idle. You could get away with a smaller cam due to the flow of these heads,for the same HP level.The dymanic compression will also be determined by the cam and pistons and chamber CC's,so do some math before you build.
With the proper set up you could make 800FWHP+ with a 427CID.But for the street with these heads,I would build a 454 SB and remember the driveline has to be upgraded too.

 

Caddie,

The SB2 heads are designed around a centrally mounted single carb intake but they are very very good.

 

The canted valve heads like the Brodix ones http://www.weldtech.com/graphics/BrodixCanted.gif
or the GM ones don't have the NASCAR limits on them as much as SB2's have on them. Most port development for a SB2 is for NASCAR where the CV heads are drag race and road race items. Such as the GM IMSA Intrepid from the early 90's that Katech built.

The GM CV 10185040 casting comes in three different versions, fully machined, semi machined and rough machined versions. This allows head porters to move the valve angles on the heads and move the spark plugs to work with the new exhaust valve locations. All pretty much for the old Pro Stock Truck class, what a cool class that was.

Here is a pretty good SB2 Head port.... http://www.weldtech.com/graphics/GP_Tech2.gif done by Gail Paully it compares in flow to the Brodix SV head above but it has a larger cross section but also a smaller chamber.

Places like Carl Foltz Eng have some bad *** SB2 and Canted Valve ports. 400cfm out of either head, but the CV seems to have more potential.

That Brodix Canted Valve example would be good on a 427 SBC street motor, but with flow like that you could easliy look at a 800hp motor. Larry Ross said it well with this:

"It's a bit of overkill for a street engine but it sure would be a conversion piece. It would be very doable and the cam will determin the idle. You could get away with a smaller cam due to the flow of these heads,for the same HP level.The dymanic compression will also be determined by the cam and pistons and chamber CC's,so do some math before you build."

As for the heads and similarities.....

SB2.2 11 x 4 intake valve angles and 8 deg exhaust valve.
CV GM 16 x 4 intake and 11 x 4 exhuast valves
CHI 3V Cleveland 9.5 x 4.25 Intake / 9.5 x 3 Exhaust
Lositio SC1 "Yates" 10 x 3 Intake 8 x 0 Exhaust

All of those heads, BBC (24 x 4 or 26 x 4 Intake and 15 or 17 x 4 Exhaust) and BBF, Toyota and Mopar NASCAR heads and Pro Stock heads are all canted valve heads. The goal is to move the valve away from the cylinder wall with more lift, therefore unshrouding the valve and flowing more air.

It also gives a really high CFM per sq in of cross section, and the smaller the bore the better.

CHI 3V 218cc runner = 138.3 - 144.9 cfm per sq in
GP Tech 2 GM SB2 = 139.8 cfm per sq in
Weld Tech CV Brodix = 145.5 cfm per sq in

Compared to non Canted Valve Heads....

HUT 921.1 18 Deg = 137.7 cfm per sq in
Brodix AP 10XAP = 138.6 cfm per sq in

Or something like a Brodix GB2000 at around 139.2 cfm per sq in

That's really high end stuff, where we normally use heads like:

270cfm LT1's = 128.5 cfm per sq in
300cfm TFS 23 deg heads = 128.7 cfm per sq in
325cfm LS6 castings = 121.5 cfm per sq in

And all of those are awesome for what we do with them too.

So you can see a jump in CFM per sq in from the street stuff (120-130 cfm per sq in) to the better non canted valve stuff (130-139) and then the canted valve stuff (139-146)

It's not really the be all end all either cfm per sq in, Larry Meaux's HP per CFM flow factor is a much better way to tell how good a head is. The cross section as he said above.....

"Port Volume "should be" just the "result" of the correct Cross-sectional Area for the desired engine RPM range.(with a given port centerline length)"

A smaller cross section with more flow (higher CFM per sq in) is just better for a smaller or lower RPM motor, that should for the same peak HP level give more average HP and TQ below the HP peak. That is if the port doesn't have any bad spots in it with too high of a velocity or a dead spot etc.... That's why the flow factor is also a good way to look at it.

Honestly those CHI 3V heads make me jealous of Ford small blocks. I've heard 350cfm out of the box on them all for a street car. Sad thing is that the heads will not catch on with the average Ford guy, so all the LT1 guys can sleep at night.

Bret

 

I had a set of Blue Thunder's for my 408 Ford that Richard did for me that would flow 411CFM on a 4.125 bore and 396 on a 4.030 with a 2.2 intake and a 1.710 exhaust and it ran preeeety good on motor and a lot better on hose.Ahh Laa 8.49 on a 200 horse shot,ran 9.20's@149 on motor 3100LBS with 10" tires and glide.
If I were going to get a set of SB2's done I would send them to Greg Well,but bring your check book.He can make ice water flow in hell.

 

Wow, thanks for the info guys! So basically the CV heads stem from the fact that they have fewer restrictions on them? Like they were made for power without compromise?

Glad to hear that they can work well on a 427 or 434 street engine. I thought about converting a set to use on a 396 LT1, but the large ports made me weary of using such a large head. So going with a larger, and better, GenI block looks like a good solution (and economical).

BTW, has anyone heard anything else about Darren's SB2.2-headed 410 LT1? Haven't heard anything in a while.

[edit]- 1racerdude, you mention using these on a 454SB. I know both the dart and WP blocks can go out to this much displacement, but from reading on another board someone (supposedly and engine builder, i'll have to look it up again) said that those setups have a horrible bore/stroke ratio and recommended using a 427 or 434 instead. Didn't really elaborate why, but is he justified? Would the 454 wear out quicker? Would the 427/434 be more reliable or durable? More longevity?

 

Bore/stroke ratio rod/stroke ratio bahhh

Cubes are always helpfull, these ratios I think guys get too stuck on. Basically the bore that will move enough wind for your set of heads and the stroke that gives you a tolerable piston speed at max RPM depending on your parts is what you are really looking for. As Rheir Morrison says the connecting rods job is to connect the piston to the crank, the size really doesn't matter. Some guys want the most rod a motor can give them other guys want a rod that's 2" longer than the stroke, this is usually the big debateable mystery in engine building.

A World or Dart Block can go 4.200" bore x 4.125" stroke to get you 457 cubes. Not much room left for a 6" rod in there, in fact a tall deck block or a 5.85" rod would be better but give you some side loading.

The side loading of the piston with a short rod will wear faster that's where the tall deck helps. You either can put more rod in the motor OR run a longer skirt that makes the piston stable in the bore.

Bret

 

Bret

Very, very good. You blow me away on some of this stuff.

 

SB2.2 Port CenterLine Lengths (CNC Hendricks MotorSports 2.180/1.600) 2004

Intake Roof= 7.100 Floor= 4.415 Length= 5.758
Exhaust Roof= 4.565 Floor= 2.680 Length= 3.623

FlowFixture = 4.125 Bore no-pipe on Exhaust
SF-600 @ 28" 2.180-1.600 valves (Hendricks CNC)
Lift---Intake---Exhaust
.200--142.3---106.7
.300--218.8---145.6
.400--288.6---184.0
.450--317.3
.500--336.7---211.3
.550--347.7
.600--358.7---235.6
.650--355.2
.700--354.8---252.3
.750--354.4
.800--356.0---262.9
.850--357.6
---------------------------------------------
Canted-valve 2.200/1.550 ported by Meaux in March 2000
FlowFixture = 4.125 Bore no-pipe on Exhaust
SF-600 @ 28" 2.200-1.550 valves (maxed-out, no welding, stock locations)
Lift---Intake---Exhaust
.200--140.1---99.0
.300--213.0---150.3
.400--286.7---192.5
.450--315.3
.500--335.1---228.4
.550--354.4
.600--370.1---249.7
.650--381.6
.700--386.7---261.4
.750--391.6
.800--397.8---267.2
.850--403.2

the Canted SBC has a little larger Intake valve 2.200 -vs- 2.180 (SB2.2)
and a little smaller Exhaust valve 1.550 -vs- 1.600 (SB2.2)
thats the closest valve sizes i have Flow info for a comparison,
usually install 2.225 , 2.250, or even 2.300 in Canted-valve SBC head

i've gotten higher Flow with Canted-Valve SBC with 2.250 to 2.300 (welded
moved-over) in the 415 to 425 CFM range on my FlowBench which is a little on the

conservative side .

there's more HP potential with the Canted-valve heads
but the SB2.2 heads are very good w/single 4-Barrell
where as the Canted-valve heads like a tunnel-ram 2-4 barrell setup

 

Holy *****!!!

Is it possible for a 434 to eat that much air under 7K rpm?

 

I'm like Bret,SOME people get lost in the numbers.A 427-454 with SB2 heads will make a killer set up,800+FWHP. A short rod motor is not going to wear out in 5000 miles so go for it.A short rod will make more TQ down low and long rods will make HP up high(8000+).There is not a nickles worth of difference in a 5.7 to a 6.0 rod length.When I say long I mean 6.250+.

 

Is it just me, or does the hp curve of a Cup engine look very much like the intake flow curve; they both hang no almost forever after their peaking point.

I'll agree that Larry's bench is a little conservative.

"Underpromise...overdeliver" seems to be his MO.

I like that in a head porter.

 

OldSStroker ....i was expecting the Flow numbers would be higher than this for the Hendricks SB2.2 NASCAR heads ??

more like these numbers
http://www.weldtech.com/graphics/GP_Tech2.gif

a local Racer is going to put on a 440+ cid SBC just for DragRacing
welding the original intake up to use a Dominator carb
be interesting to see HP/TQ numbers

the stems are MM , approx .250's on Intakes and .270's on exhaust
the intake stems as small as the 1/4" valve cover bolts

 

Yeah, 6 mm (.236) and 7 mm (.276) stems being used. Check Stealth Engrg. and Tech. Hollow stems. Ti of course. Close to $1500 for eight intakes. "How fast do you want to go?"

I think a Cup intake valve spends considerable time above .600 especially with rocker ratios around 2:1. That's got to be a lot of area under the lift curve, don't you think? Running those number thru the ole simulator could shed some light on it. Maybe those were "plate" heads?? What was the cross-section?

Also 4.125 is small for a Cup bore. Flow might be a little better with 4.18 bores.

My random thoughts.