BBM head info

[chilly460]

I have BBMs on my mild 390 with a little 224* roller, and I have a set of TFS sitting here as well....maybe a back to back is in order

I guess I don't see where the debate is, TFS flows more through a smaller port for $600 less.  I don't know enough to know if somehow wet flow is horrible on the TFS, or if they stall early (every indication is they're fine for most hydraulic roller combos that aren't 500ci+), but doesn't seem like it's an issue as they seem to dyno in line with expectations. 

Any BBM/Edelbrock that can run with them is being ported which brings the port energy into question as they're already larger.  As stated, I'm sure there are applications where the air speed gets too high with the TFS and a larger port would work better, does anyone know how much the TFS can be opened?  My understanding is TFS is usually pretty good about leaving meat in the ports.  I know it's sort of unchartered territory to go grinding on CNC'd heads, but small block guys do it all the time.

[blykins]

I have BBMs on my mild 390 with a little 224* roller, and I have a set of TFS sitting here as well....maybe a back to back is in order

I guess I don't see where the debate is, TFS flows more through a smaller port for $600 less.  I don't know enough to know if somehow wet flow is horrible on the TFS, or if they stall early (every indication is they're fine for most hydraulic roller combos that aren't 500ci+), but doesn't seem like it's an issue as they seem to dyno in line with expectations. 

Any BBM/Edelbrock that can run with them is being ported which brings the port energy into question as they're already larger.  As stated, I'm sure there are applications where the air speed gets too high with the TFS and a larger port would work better, does anyone know how much the TFS can be opened?  My understanding is TFS is usually pretty good about leaving meat in the ports.  I know it's sort of unchartered territory to go grinding on CNC'd heads, but small block guys do it all the time.

We have a port setup for them that increases the port volume by 10cc and increases the cfm to right at 360 cfm.  Works well on the larger 496-500ci street engines.  Haven't tried it yet on a zippy smaller engine.

[Yellow Truck]

With all due respect to everyone here, I'm not nowhere near off the knowledge and experience as the rest of y'all here , it would seem to me in my humble and honest opinion that unless a person is wanting to squeeze every last hp and tq out of a motor, that either the TFS or BBM would be an excellent choice . It really just boils down to availability and how soon a person wants to get a motor together. With all that said if it were me I would go with the BBM'S.

To each his own. I have a set of BBM heads, and had I been given the choice I'd have gone TFS even if it meant waiting. Still curious what the driving experience difference would be. In my truck I can break the tires loose up to 35 mph, but it is nose heavy so that isn't really a big test.

[mbrunson427]

I have 2 problems with the TFS heads. 1) rocker stands require milling, they missed the mark a little bit here. I realize it's a totally fixable situation, but a little annoying. 2) the bigger problem is the port design. When flowing the TFS heads they go turbulent/backwards after .630-.640" of lift. For most street engines this doesn't affect anything, but it bugs me that they let it roll off the assembly line like this. They had to of known it occurs, because even I know it does, but they didn't bother to rectify the problem. Seems to me that they got 94% of the way there and let it roll before making it to 100%.

As for an opinion between the 2 brands, I don't think I really have one. There's a fair bit of innovation that sounds like it's going to hit the FE market within the next year. Good time to be an FE guy.

[Tommy-T]

It's wonderful that there are so many cylinder head choices for these dinosaurs. From Blairs Pro Ports and Jay's FE Mega Power stuff, to the more street oriented TFS, BBM, Pro Maxx, and Edelbrock stuff.
It would appear that the TFS has a repeatable advantage...right now. AND they're the cheapest. When does that ever happen? All seem pretty equal in quality.

The catch is, unless your car dead hooks 'n books 20hp is fairly inconsequential. But it's everything to a guy that sells motors. If you can fry 'em through 3rd with iron heads, you'll fry 'em better with 50 more hp, I guess, too.

My little cylinder head story? I built my first 427, actually a 452, in 1985. It had some milled-to-death Hi Riser heads that I bought at FPP. They were assembled by stock racer Greg Foreman. It was always a crap shoot when I would put the top end together if it would leak water because I didn't want to mill the factory Hi Riser intake. When sealed up the car ran very good, low 11's with a .590 lift 300 advertised duration single pattern cam ground on 108 centers. I drove it all over the place here in L.A.
I really got tired of the "Hi Riser Hassle". When I found out that Edelbrock was coming out with an FE head I headed over to legendary Blairs Speed Shop in Pasadena. I told Phil Lukens that as soon as these heads are actually available to get some. Some 76cc heads soon showed up.
I had Blair's install 2.19 and 1.75 valves and do a bowl clean up. I matched the heads with a Port-O-Sonic intake manifold.

Took it to the track and guess what? It ran the same. Boy, was it nice to have some new non-beat-up-crap!
I have been a fan of the Edelbrock head, and all Edelbrock products, for a long time. I remember Mark Artis and the Texas Thunder boys running in the 9's with much reworked Edelbrock heads. The TFS is an Edelbrock head and so are Blairs Pro Ports. They certainly have gone the extra mile for us FE guys.

[1968galaxie]

Two thumbs up Tommy-T
Well said!!

[WerbyFord]

Sad that it's so hard to get parts right now.
I was about ready to Gonkulate this thing after another in-depth look at the C8AX-D cam.
Then I read the CNG part - I have never done much with CNG but it seems like the fuel then takes up a lot of volume - where is it sprayed into the engine?
At the carb base like TBI, or at the head face like port injection?
Either way, that's a lot more volume of fuel+air trying to get into the cylinder.
So it looks like intake flow is all the more important.
The big "D" cam's single pattern might not be so bad here if more intake flow is needed for the extra "moles" going in.

I started looking back at the BBM vs TFS head flows - then at their websites, BBM now shows what THEY get for the BBM_CNC heads:
Eg 321 intake 226 exhaust at .500, no pipe:

https://bearblockmotors.com/bbm-ford-fe-cylinder-heads/

And then the TFS heads from their site:
Eg 317 intake 239 exhaust at .500, 2" pipe
https://static.trickflow.com/global/images/chartsguides/t/tfs-56417001-c00_pv.pdf

My impression was the TFS intake would outflow the BBM, but does that change with the CNC_BBMs?
And that is super good flow from the TFS exhaust - are they really that good?

Any flow tests of out-of-box BBM_CNC vs TFS_CNC under the same conditions?
Seems its even harder to compare flow benches than to compare dynos.

Chamber size is another issue, TFS says 70cc, BBM says 75cc but more like 80cc for CNC.
And reliability - I hate parts that dont fit and threads that strip. I think in 50 some years I've only had 2 threads strip in cast iron heads.

[frnkeore]

When you look at the BBM flow, it notes that the numbers are for 2.25 x 1.71 valves 346 x 245. The base price is for 2.15 x 1.65, a 5% and 4% difference. If you reduce the flow by those same numbers, they are 231 x 235 @ .600.

The TFS heads by their info are 332 x 245 @ .600, with 2.19 x 1.625 but, the heads that Brent had flowed where 333 x 220, a pretty big difference. I wonder where that 25 cfm went?

A big difference is that it seems from Brent's test, that the port backs up, after .600 and if you can believe BBM's numbers, they keep flowing up to .900.

So, with a high lift cam, the BBM's might be much better.

I chose the TFS because of price and that I wanted my lift to be under .650, so I could still use stock rockers. I'd sure like to have that extra 25 cfm on the Ex though. But, maybe it was just that particular set that Brent had for the test, that was the problem? IDK

[chilly460]

I don’t have info as to how Brent flowed the heads, but even doing everything correctly there’s a fairly wide margin in figures based on using a pipe, and what size is used.  TFS flowed it with a 2” which is fairly large for an FE

If you haven’t seen it, this guy does a great job showing results.  He’s fairly new to YouTube but is a fairly well known head porter and gives good info, flow info stArts around 28:00

https://youtu.be/DNfA7XD7xYM

[blykins]

Several things to note here:

Port volume plays a huge role in what a cylinder head does.   Does anyone know the port volume of the CNC ported BBM head?  The TFS heads flow 330-340 on a 169.5-170cc port and around 360 cfm on a 180cc port.   A non-CNC ported BBM head flows around 290 cfm here. 

The box stock heads do start to back up flow.   I made TFS aware of it, but I'm sure they know it, and who am I in the grand scheme of things?  However, I will say that out of the box they can do some great things, even with a much higher lift cam than what you would expect to use.   I made almost 670 hp from 449 cubic inches with a .700" gross lift camshaft.  No head work.  Any FE that makes around 1.5 hp/ci here is a pretty stout FE. 

My flow numbers on heads that I flow here do not use the pipe.  So if you're wondering why the 25cfm of exhaust flow magically disappeared, that's why.  On the ported TFS heads, they come from my porter's shop and he does use the pipe, so those numbers will reflect that. 

[My427stang]

A couple of comments

1 - I have never stripped an aluminum thread if proper engagement depth, not ham-fisted, and have yet to have an issue with any head if using good anti-seize

2 - Sealing an exhaust has less to do with torque and more to do with matching parts and good assembly, it's not like we are torquing mains

3 - In general, I'd rather have a small chamber, less piston weight than a larger chamber with more piston weight.  The second benefit is surface area and clean burn path.  The latter not a big issue with 69.8 vs 72-76 but in general.....

4 - Comparing a CnC BBM to a TFS is fine, and for big gulping, big inch, high RPM motors, is likely a valid comparison, but the small time the valve touches the lift that creates backup, the ability to touch a few areas to eliminate that, and the amount of deflection you see when running the spring pressures required for that cam, most of the guys here, including me, will never have to worry about it

5 - Comparing a CnC BBM to a TFS is also fine if someone lists price for each.  That last bit of CFM needs to be weighed against what I think is a significantly higher price (but I have never had a set of CnC BBMs in my hands)

6 - Port volume does matter as Brent said.  Huge "it depends" here, but more volume will want more overlap (in general) and to get that flow, if the BBM is significantly bigger, yes it has more potential, but the TFS works real well even with very small overlap values.  A lower flowing port like the non-CnC BBM will likely want a little bit more overlap to fill the cylinder. 

7 - 550-ish HP at 5750 from a 231 duration cam, with 114 LSA and less than 63 degrees overlap and just at  600 ft lbs.  This is a truck motor with off the shelf parts.   Sort of shows how these work for "Everyday Joe" 

I am a TFS fan, for now, had a single set of BBMs though here and they were gorgeous, never used a CnC BBM, but for me, there has to be a very good reason to shift upwards in price or downwards in flow with a standard head.  Maybe an existing build that would be too high in compression?  However, they aren't the end-all, just a real good head, and readily available

[gregaba]

Werbyford
CNG is injected into the manifold in each runner [port injection] with their own injector. It is a gas as injected and is injected at a fairly low pressure.
It is compressed only for storage as if it wasn't compressed you couldn't get enough in the tank to do any good.
I will have to use bank to bank injection at first and then after I get my MS3 will switch to sequencial [?sp].
I would be interested in a gronk on the gas only just to compare when I do get the engine in the car and dynoed.
By the was the kit cost is $1495 for everything except the storeage tank.
I have to send in my interior trunk size to see what the tank will cost.
They have a tank made for a Crown Vic that I think will fit but if not he can make dual tanks.
The Crown tank is $2900.00.
Greg

[Joe-JDC]

As stated in another place, I have flowed the CNC'd BBM heads, and they were in the 336 cfm range at .750".  The CNC combustion chamber is listed as 80 ccs.  The price for assembled BBM heads is listed as $2550.00 plus shipping, and you will have to add CNC porting on top of that plus any spring and retainer changes.  The larger valves will make a difference in flow by themselves, and using a pipe on the exhaust usually amounts to 20 cfm difference at the top of the lift on a sliding scale.  Less at lower lifts, more at higher lifts.  I don't usually flow anything higher than .800" since most folks usually have a camshaft with less than .650" lift on the street.  I can flow to 1.100", but that is on special requests.   Joe-JDC

[Stangman]

I’m not going to pretend I know cylinder heads like some of the guys on here but I myself have out of the box survivals, I believe they flow the same as an out of the box BBM. I’m under the impression that the TFS heads come CNCd out of the box. I believe the CNCd Survivals flow 360 cfm is there a reason why they don’t get bunched in in this conversation. Now when I got my Survivals there was no BBMs or TFS so at the time I had thought they were way ahead of what was out there.

[gregaba]

For anyone interested I had just scaned the directions for the install of the ecu for the CNG and missed some of it.
After reading the whole thing the ECU is a port injection unit and you just imput the fireing order for the injectors.
Greg