412 ci, FE, FT cam

[frnkeore]

I'm trying to design a SFT cam for my FE Ford, using Howards cam lobes. Here are the basic specs:

4.15 x 3.81 steel, offset ground, 412 ci
6.56 rods, 2.1 x .927 H-beam
Ross FT pistons 1.5mm, 3mm
TFS heads, 11/32 valves, 333 x 240 w/pipe @ .600, they back up, after about .650
Intake, TR 2x 660 4150
CR 10.8
4 stage dry sump
108 LSA x 104 ICL
Wanting 7.1 - 7.4k rpm hp peak
I haven't bought the headers yet, it is a dyno mule

My limitations on the cam are, I would like under .650 max lift/1.76 rockers with shell lifters and 3/8 push rods

I'm looking at the Howards, .368 Brookshire lobes that range from 259 - 267 @ .050 for intakes but, because of the lift limitation, I'm having trouble finding a Ex lobe, with 8 - 10 more duration, although I can do it with a 259/267 combo, I don't think it's enough to get to the ~7200 rpm range, I'm looking for.

Can I do this with the Howards std lobes, on the Ex side and get blow down and overlap and not have the mid lift of the Brookshire lobes.

This is a list of proposed lobe combo's:

Howard
In
F2633683 307 292 263 175 0.368 0.016 net .631 - Brookshire
Ex
bf270370 316 305 270 175 0.370 0.022 net .629
--------------------------------------------------------------
In
F2673683 311 296 267 179 0.368 0.016 net .631 - Brookshire
Ex
bf274370 320 309 274 182 0.370 0.022 net .629
or
bf278382 324 313 278 186 0.382 0.022 net .650

And what rpm range, would I get with this Brookshire combo?
F2593683 303 288 259 171 0.368 0.016 net .631
F2673683 311 296 267 179 0.368 0.016 net .631

[af2]

The blow down thing has me not understanding?

[frnkeore]

The initial blow down, when the valve starts to open.

[F-BIRD'88]

Howards has only a limited number of UDHarold's cam lobes.. Contact Bullet Racing Cams or Lunati. Both have UDHarolds flat tappet Ford lifter .875" specific cam lobes although you can also look at the .842" lifter cam lobes too. You can download these lobe lists.

[F-BIRD'88]

I think the 108lsa. 104 in c/L is throwing a wrench in it.

Why? If you want peak hp 7000+ rpm with a TR you got to feed it up high.

Comp has a series of .367" lobe lift. low lift roller cams that have the durations needed to feed your 412 FE

"CR Lift Rule Rollers" If thats your hard max lift limit
this is how to get enough cam under it to do what you want done.

[frnkeore]

F-Bird,
Thank you for the suggestions, especially the CR lobes. I may go with them, after the SFT cam. As I said, this is a dyno mule and I will be testing cams and intakes (including MFI) and some header stuff. So, the CR lobes will be the perfect test, regarding how much HP might be expected, with just a swap to a roller, all other things equal.

My absolute max lobe lift is .382 @ .020 lash. This stuff becomes a slippery slope so, that's where I draw the line.

I'm not married to the 108 LSA, I plan to test different LSA, also.

I looked at Bullets, online catalog and found only "F" and "NF" lobes. They are slower and higher lift than the Howards, Brookshire's. I looked on Lunati's site couldn't find anything, regarding Brookshire lobes, also.

I would love to get a .875 lifter Brookshire catalog. I normally use the Howards .875 lobes but, they have to much lift and Ben has moved on so, I can't ask him to shorten them up (Ben was a great guy, he'd do anything within reason for you). I don't think they have a new engineer yet, to replace him, either.

[mag2555]

Frank if the intake flow goes regressive at .650” when testing without a intake bolted on then I can guarantee you it will back up at .600” lift once the intake is bolted on, or in the least you will note pumping taking place around your test pressure as seen on the vertical manometer.

This pumping indicates the start of the flow mass passing over the short turn being blocked from merging with the main flow mass swirling out of the chamber to locate / center itself in the less restrictive center and Exh side of the cylinder bore.

[F-BIRD'88]

I found a series of howards flat tappet lobes that have the lift and .050" duration required.
eg: Howards # bf268382. and #bf278382

These are BBC lobes but will run fine in your FE.

There are low lift .367" versions of these too.

[F-BIRD'88]

Why do you assume that .650" net valve lift is the flow limit? Even if flow flattens above .650" the valce spends MORE TIME open @.650". If the cam provides more peak valve lift.. The amount of net open area/ time is greater.
It also allow the valce to dynamicly track the lobe better because the extra lift allows the valve to slow down to go over the nose.
The valve will have better running dynamics.
What goes on @ the valve is what matters.
But I believe that the engine will want 268 @.050" intake valve timing at least. 268-268 cam. 268-278 cam 278-278 cam. The tunnel ram induction is going to want to eat... Let it eat to get max HP on your FE.
Of course a roller is going to have more open area.

[F-BIRD'88]

Your rockers with a labeled "nominal" rocker ratio 1.76"

Will not show the same constant measured RR at all lifts.
The RR at/ near max open lift may be different than 1.76:1 exactly.

[F-BIRD'88]

Mike Jones. CAMKING. may be able to help you with these 3 issues if you can give him enough info on your combo. You may need to measure some stuff for him to analyze. Including the intake manifold runners.

1.true rocker ratio @high lifts.
2.valve dynamics
3.Performance effect above .650" net running lift

IMHO you can do so much more with a roller and it will last longer too. I don't see a problem with running more than .650" net valve lift and see some benefits 1.,2,3,
I don't think your 259/267 cam is going to be enough to max HP.

[cgarb]

There will be no durability issues with a cam lasting in an FE Ford. If it's a good quality cam and lifters it will last the life of the motor. FE ford's have large lobes on them, they wear very well. I have a friend who raced FE ford's for longer than I've been alive and he has camshafts in his shop that have been in multiple motors and are still good.

[frnkeore]

I'm trying to design a SFT cam for my FE Ford, using Howards cam lobes. Here are the basic specs:

4.15 x 3.81 steel, offset ground, 412 ci
6.56 rods, 2.1 x .927 H-beam
Ross FT pistons 1.5mm, 3mm
TFS heads, 11/32 valves, 333 x 240 w/pipe @ .600, they back up, after about .650
Intake, TR 2x 660 4150
CR 10.8
4 stage dry sump
108 LSA x 104 ICL
Wanting 7.1 - 7.4k rpm hp peak
I haven't bought the headers yet, it is a dyno mule

My limitations on the cam are, I would like under .650 max lift/1.76 rockers with shell lifters and 3/8 push rods

I'm looking at the Howards, .368 Brookshire lobes that range from 259 - 267 @ .050 for intakes but, because of the lift limitation, I'm having trouble finding a Ex lobe, with 8 - 10 more duration, although I can do it with a 259/267 combo, I don't think it's enough to get to the ~7200 rpm range, I'm looking for.

Can I do this with the Howards std lobes, on the Ex side and get blow down and overlap and not have the mid lift of the Brookshire lobes.

This is a list of proposed lobe combo's:

Howard
In
F2633683 307 292 263 175 0.368 0.016 net .631 - Brookshire
Ex
bf270370 316 305 270 175 0.370 0.022 net .629
--------------------------------------------------------------
In
F2673683 311 296 267 179 0.368 0.016 net .631 - Brookshire
Ex
bf274370 320 309 274 182 0.370 0.022 net .629
or
bf278382 324 313 278 186 0.382 0.022 net .650
--------------------------------------------------------------------------
And what rpm range, would I get with this Brookshire combo?
F2593683 303 288 259 171 0.368 0.016 net .631
F2673683 311 296 267 179 0.368 0.016 net .631
______________________________________________________________________________

I found a series of howards flat tappet lobes that have the lift and .050" duration required.
eg: Howards # bf268382. and #bf278382

These are BBC lobes but will run fine in your FE.

There are low lift .367" versions of these too.

Note that the bf278382 number, is the same as I was suggesting with a Brookshire 267 intake lobe but, the .200 duration of the 267 Brookshire is 3° more than the bf 268382 lobe.

I'm wanting the ramps of the Brookshire lobes, because of what I understand, is there better stability. The valve train is the issue on lift, if I could go .700+ I'd use the Howards .875 lobes but, the rocker upgrade for that is $1500+ on a FE. But, I'm also concerned about the port. This head has a flow report on the Weiss site. It's said that it doesn't just stop flowing at .600 but actually backs up. So, the lift limit, is two fold. One other reason that the lift isn't so important to me, is that Blair Patrick's EMC winning 400 ci engine, only had a .600 lift, roller cam, with much less timing and probably, a little less head flow, to produce 1.5 hp per ci, peaking at 7.1k, as I remember.

I'm wanting the engine to be durable but, the cams that will run in it, don't have to be, as they will only run a small number of hours, at most.

[frnkeore]

Frank if the intake flow goes regressive at .650” when testing without a intake bolted on then I can guarantee you it will back up at .600” lift once the intake is bolted on, or in the least you will note pumping taking place around your test pressure as seen on the vertical manometer.

This pumping indicates the start of the flow mass passing over the short turn being blocked from merging with the main flow mass swirling out of the chamber to locate / center itself in the less restrictive center and Exh side of the cylinder bore.

Steve,
Thank you, that may indeed be why these ports back up. All I know is that they back up, after .600 and that's what I have to work with/around.

Even though the flow is high, they are not race heads but, they are used on the street a lot. Blair Patrick ports Edelbrock castings to at least 350 cfm and they don't back up but, they are another $1000 over these.

It's all about the money!

Thanks again, Steve.

[canada1]

I will certainly follow this build!
Regarding cylinder head turbulence at 0.650" lift - (with the very short FE port) one must evaluate turbulence with the intake attached.
It will certainly have an effect - possibly moving up where the turbulence starts.

The TFS heads have very decent 0.300, 0.400, and 0.500" flow figures. You will likely require less intake lobe than with other head castings for the same peak power rpm. For higher rpm you may also want the ICL closer to 110 than 104 - as you will not require as advanced intake lobe timing.
It looks like you will be moving the camshaft around during your testing
Can't wait to see the results.

I would not be surprised with 600+ HP