KC2 cylinder head camshaft solution

[funsummer]

Posted the flow numbers from a local head porter.
I am a little concerned at the numbers.
brand new KC stage 2 heads, never run.
They have been on my shelf for 2 years due to delays.
As seen they were very lightly cleaned up locally.
They are fitted with 3/8 stem valves.

Can a camshaft profile with enough split duration to make these heads work ok?
Local head porter does not have FE experience but did suggest a large duration split, low lift exhaust to keep energy in port.
He said I should expect a weird profile.

Joel R

[blykins]

I would expect a little more out of them, but flow benches vary, just like dynos. 

Ok, I had to edit because I found out that he did flow with a pipe...

To answer your question, yes, that's no problem to get an optimal camshaft.  If I were grinding a cam for a 63% ratio, I would add about 8-10 degrees split between intake and exhaust duration.  That's a general statement as there are a lot of other variables involved. 

A lot of Ford factory heads are right there, or even worse, and we make them perform just fine. 

[Joe-JDC]

Something doesn't look right with that flow sheet.  Those flow numbers are similar to the KC-I heads.  I have flowed several sets of the Stage II heads, and the intakes are always over 330 cfm, and the exhausts 230ish cfm without a pipe.  I know flow benches are different, but over the last 30 years of flowing heads and intakes, my bench is about 10 cfm more conservative than most.  Joe-JDC

[funsummer]

Joe,
I purchased these from KC and certainly paid for stage 2.
Also paid for postage to Australia, which allways makes it hard if things don’t work out as planned.
I certainly was expecting numbers more like you mentioned.
These are for a 4.080 bore. Could that be the reason?
Valve heads are very shrouded in chamber.

Any suggestions for a Hyd roller for street/strip. Perform rpm intake, c4auto 3.98 gear.
Galaxie 65 heavy car.
6000-6200 max rpm
Joel

[scott foxwell]

Just sent you a P.  You're going to need a custom grind to get the most out of your combination.

[blykins]

Joe,
I purchased these from KC and certainly paid for stage 2.
Also paid for postage to Australia, which allways makes it hard if things don’t work out as planned.
I certainly was expecting numbers more like you mentioned.
These are for a 4.080 bore. Could that be the reason?
Valve heads are very shrouded in chamber.

Any suggestions for a Hyd roller for street/strip. Perform rpm intake, c4auto 3.98 gear.
Galaxie 65 heavy car.
6000-6200 max rpm
Joel

What displacement?   Power brakes?  What pistons are you using?  Compression ratio?  Are the heads assembled?  Already have valve springs?  If so, what are spring pressures and what is install height/coil bind?   How do you want it to sound at idle?

[funsummer]

390 stroked to 444
Has power brakes
Mahle flat tops on zero deck so 10.1 to 11 depending on chamber cc and gasket, have .041” Fel-Pro or .036” cometics
Currently at 77cc chambers
Heads currently stripped and will buy springs to suit cam.
New 2800 high stall converter and 3.89 gear.
Would like to have rough idle
Crites headers
T&D street rockers
Need to buy new master cylinder to suit new willwood front disc package so if vacuum not enough then willing to remove booster.
Joel

[blykins]

Mahle's flat top for a 445 has a 7cc volume.  A 77cc chamber sitting at zero with a .041" Felpro gives you 10.66:1 by the calculator.  You'll probably be a hair under that when you factor in crevice volume. 

For a 5500 rpm hp peak with a 6000-6200 rpm shift point, I'd be at:  235/243 @ .050", 291/299 seat, 110 LSA on a 104 ICL, with .576"/.588" lift. 

You're in a Catch-22 with longer duration hydraulic rollers on FE's.  You want a less aggressive lobe with the heavier valves and to keep valvetrain noise down, but when you go with a less aggressive lobe, the advertised duration goes up and you gain overlap.  It's a balancing act.  You're at 75 degrees overlap with this one.  If you're a good tuner, you can make it work with power brakes, but vacuum will be marginal at this point.   I could be talked into a 112 LSA to help with that, but I think you need a little tighter LSA to work with a larger port that doesn't flow as well. 

This would be a billet steel core.  You would need to run a steel distributor gear. 

Valve spring pressures need to be 140-150 seat and 350-360 open.  I would run a beehive or a small diameter (1.200-1.300") dual spring with tool steel retainers. 

[CaptCobrajet]

You need a 112.......it will cost about 20 hp compared to a 110 in that combo, but you gotta have brakes.

[blykins]

If he's willing to skip the booster and go manual, I'd tighten her up and let her eat.

[funsummer]

Brent,
Appreciate input.

110 LSA sounds like fun
112 LSA seems sensible.

What would one expect the differences to be in regards to idle rpm, idle quality, general street manners and lastly horse power.
As this is a street car so that’s a logical order of importance.

[scott foxwell]

A cam should not be analyzed or chosen based on LSA. It's not a design criteria, it's simply a result of the valve events. It's a byproduct. It's like trying to choose a cam based on .050 duration numbers. If the opening and closing events are correct, the LSA will be what it is.

[blykins]

Idle rpm wouldn't change. 

Idle quality/sound comes from the amount of overlap that you have.  The "radical" sound that you hear from a camshaft is the sound of both valves being open at the same time.  With the 110 LSA you have 75 degrees of overlap.  With the 112, you have 71.  Both cams would sound great, but the 110 would be a hair more "noticeable". 

As far as street manners, I think it would be a toss up.  I like an advanced intake centerline on my street stuff, so a 110 would be ground on a 104 ICL and I haven't ran the numbers, but I would most likely put the 112 on a 104 or 106.  You would have more vacuum with the 112 lobe center, so if you're bent on using vacuum-assisted brakes, that would be the way to go.  Vacuum with the 110 would be marginal at best.   

On horsepower, we would probably have to put them both on the pump to definitely qualify a difference, but I'm with Blair on this one....I think there would be a horsepower bump from the 110 LSA.  For one, I think the torque would be a little higher and as I mentioned earlier, I would rather have a tighter lobe center with a larger, lazier intake port. 

If you're focused on streetability, I would go with the wider lobe center.  If you're willing to run manual brakes and are looking to optimize the combination for power, I'd go 110. 

[blykins]

Scott, check your email please....

[fastback 427]

You guys should just duke it out and get it over with. Really. The measuring contest is starting to to get old. I usually dont mind a little drama. Brent, we know all about your great fe builds, they are posted here for all to see. Scott, I've been told you build some awsome bbc engines, but i don't look at those forums...