Cam specs for Ported Heads

[XfireZ51]

As I have followed Todd's exploits with his 427 and interesting cam profile,
it occurred to ask whether the stock cam profile is optimum for the additional airflow available through ported top end and heads? Not sure how much more airflow a set of GVD heads provides, but it would seem logical that using stock cams doesn't exploit potential of the added airflow. Is it a matter of degreeing the cams differently or require a cam regrind to add more lift and/or duration?

[flyin ryan]

As I have followed Todd's exploits with his 427 and interesting cam profile,
it occurred to ask whether the stock cam profile is optimum for the additional airflow available through ported top end and heads? Not sure how much more airflow a set of GVD heads provides, but it would seem logical that using stock cams doesn't exploit potential of the added airflow. Is it a matter of degreeing the cams differently or require a cam regrind to add more lift and/or duration?'Optimum?' Um'....That'd be a no. Also, can't just simply degree the cams to do what you need them to do, in this instance. Never a bad thing to degree & will/may help a bit, but that's it.

[XfireZ51]

'Optimum?' Um'....That'd be a no. Also, can't just simply degree the cams to do what you need them to do, in this instance. Never a bad thing to degree & will/may help a bit, but that's it.

FR,

That's why I asked. Here you have all this additional air and ....

[flyin ryan]

Yup...You got er', that's the deal in a nutshell ;)

[scholtmj]

I'm curious too. Given a set of heads ported to "today's" standards, what cams would work best with ported heads on a 350, 368...so on. Drivability/intended use aside.

Sounds like the "while I'm there" bug has hit. Xfire just spent lots of $$ on ported heads and doesn't want to put stock cams back in! I'm in the same spot. :thumbsup:

[XfireZ51]

I'm curious too. Given a set of heads ported to "today's" standards, what cams would work best with ported heads on a 350, 368...so on. Drivability/intended use aside.

Sounds like the "while I'm there" bug has hit. Xfire just spent lots of $$ on ported heads and doesn't want to put stock cams back in! I'm in the same spot. :thumbsup:

When I re-did my Xfire I read up on cam selection including some of Vizard's work. Seems obvious that the stock cams, altho working well, don't take full advantage of the additional airflow. If you're going to do the job, try to maximize the power output. On an SBC, it's easy enough to play with cams.
The LT5, not so much. If Marc H. is lurking maybe he could chime
in.

[Pete]

I will put it this way.
On a stock motor the stock cams are underpowered by the heads/intake.
After porting, stock cams are the weak link/underpowered.

We know when you port the heads/intake we pick up 30-40hp .

That tells me after porting we have reached stock cams potential,since after we add bigger cams we pick up another 25-30hp which means we have not reached the heads potential.

I hope i said that right.:)
Pete

PS
I would also like to know the best cam specs.
I know we could get 500rwhp from a 350ci the question is how much driveability will we have to give up.
If ported LT5 heads have 255cc intake port and 340cfm what would be the right cam for max power anybody have a cam/head caculator.
I would like to try a bigger intake cams maybe in the future when money starts to grow on trees,it gets a bit pricey, unless i find a low priced SGC Stage III intakes or maybe borow a set.
Man i would love to get another 15-20hp and hit 130+mph :-)




.

[flyin ryan]

I hope i said that right.:)
Pete

PS
I would also like to know the best cam specs.



.Said just fine Pete :cheers:. This is a trap guys fall into, looking for the 'Perfect' cam(s)...:thumbsdo:, doesn't exsist. Take that cam/head calculator or whatever they're called & throw it in the bush. I never used one, never have & never will. Way, WAY too many variables to compute. Trial & error, that's the game, suck's major big time with an LT-5 though, no doubt about that. When I'm looking at/for a cam profile I'll have my guys grind, I take all the info I have but at the end of the day, honestly, it ends up being instict. Always remember to error on the small side, if on the fence. Most guys on here should follow Pete's lead, if you ask me. For his combo, his car works dang good!....That's not small talk.

[XfireZ51]

I'm not one to discount school of hard knocks approach. Especially knowing Pete personally, I respect his knowledge and hard work. On the other hand, there's physics involved, not black magic. That allows modeling and simulation especially with the computing power now available. At the very least, I would be interested in seeing what the calcs say. Secondly, it would be of interest to compare the theoretical with the empirical.

[LGAFF]

there's physics involved, not black magic.


Actually I walked in on Pete once in his garage while he was in the middle of sacrificing three chickens and a goat....the next day he ran 129mph.

So maybe alittle black magic involved.

[XfireZ51]

Actually I walked in on Pete once in his garage while he was in the middle of sacrificing three chickens and a goat....the next day he ran 129mph.

So maybe alittle black magic involved.

Is that what he called it? "Sacrificing" a goat?

[Pete]

Actually I walked in on Pete once in his garage while he was in the middle of sacrificing three chickens and a goat....the next day he ran 129mph.

So maybe alittle black magic involved.


LMFAO
Lee,what you see in my garage stays in my garage.
"No garage for you 1 year" :)
Doms,suspension is almost over,couple more weeks :thumbsup:
Pete

[Bob G]

I'm not one to discount school of hard knocks approach. Especially knowing Pete personally, I respect his knowledge and hard work. On the other hand, there's physics involved, not black magic. That allows modeling and simulation especially with the computing power now available. At the very least, I would be interested in seeing what the calcs say. Secondly, it would be of interest to compare the theoretical with the empirical.

Wouldn't you have to have someone who specializes in 4cam engines and one with the same valve angles, chamber size & configuration ? then throw in limited valve lift & rpm [weak chains]
If you know someone like this Please !!! get us the info
Thanks
Bob G
427LT5

[scholtmj]

This might be blasphemy, but shouldn't Ford mod motor guys have a good idea about cam size vs. flow data for 4-valve heads?

[XfireZ51]

This might be blasphemy, but shouldn't Ford mod motor guys have a good idea about cam size vs. flow data for 4-valve heads?

Good point. I'm also curious about what software tool Todd P. used (if at all) to develop the cam profile he recently posted on the thread about his 427 project.
Here's his latest:
http://www.zr1.net/forum/showthread.php?t=11411&page=3
What Todd is doing is very different from what's been attempted before. We certainly have much more data regarding either stock or ported heads on a stock short block. I'm just interested in using a similar process for the for the "run of the mill" LT-5 mod. If its been done before, I'd be interested in the results. :cheers:

[Sgreg]

I'm curious too. Given a set of heads ported to "today's" standards, what cams would work best with ported heads on a 350, 368...so on. Drivability/intended use aside.

Sounds like the "while I'm there" bug has hit. Xfire just spent lots of $$ on ported heads and doesn't want to put stock cams back in! I'm in the same spot. :thumbsup:

I am about to be in the same spot. How about a limited group order and a discount !!!??? I have a 350 cube motor and will have ported top end inc. TB. Just about out of money for cam grinding even though I have a core set of stock ones to hand over. Would love to pick up that extra 20-25 ponies at the wheel.

[LGAFF]

I have pointed this out in the past Sean Hyland builds 600hp Ford DOHC Cobra motors.....also has developed cams.

[Paul Workman]

I have pointed this out in the past Sean Hyland builds 600hp Ford DOHC Cobra motors.....also has developed cams.

Lee,

Could you post the ISBN# for that S. Hyland book? (ISBN# usually on the back - often next to the a bar-code.)

It would make for an interesting read. :thumbsup:

P.

[Pete]

Good point. I'm also curious about what software tool Todd P. used (if at all) to develop the cam profile he recently posted on the thread about his 427 project.
Here's his latest:
http://www.zr1.net/forum/showthread.php?t=11411&page=3
What Todd is doing is very different from what's been attempted before. We certainly have much more data regarding either stock or ported heads on a stock short block. I'm just interested in using a similar process for the for the "run of the mill" LT-5 mod. If its been done before, I'd be interested in the results. :cheers:


Here's my take.

I doubt it but, if Todd were to loose any low end power with his cam choice he will make up with C.I.'s.

Basicly if Todd makes for example 650RWHP @ 7k RPM i'm pretty sure he won't be making zero power at 2k or 3k RPM.
I can't wait to see how it turns out.

Pete

[ALZR1]

Here's my take.

I doubt it but, if Todd were to loose any low end power with his cam choice he will make up with C.I.'s.

Basicly if Todd makes for example 650RWHP @ 7k RPM i'm pretty sure he won't be making zero power at 2k or 3k RPM.
I can't wait to see how it turns out.

Pete

650RWHP @ 7k RPM I'd love to see that one.


AL.

[tpepmeie]

PS
I would also like to know the best cam specs.
I know we could get 500rwhp from a 350ci the question is how much driveability will we have to give up.
If ported LT5 heads have 255cc intake port and 340cfm what would be the right cam for max power anybody have a cam/head caculator.
I would like to try a bigger intake cams maybe in the future when money starts to grow on trees,it gets a bit pricey, unless i find a low priced SGC Stage III intakes or maybe borow a set.
Man i would love to get another 15-20hp and hit 130+mph :-).

Pete, I'll hazard a guess. For a 350 with peak power around 7000 rpm, maybe like 284 seat duration (which could be anywhere from 239-244 @0.050"), and .430 lift. Exhaust 10 to 15 degrees smaller duration and .400-.420 lift.

Corey did a 372 for Bonneville with Stage 3 cams, and maximum porting stock valves. Made great power for its size.

Todd

[XfireZ51]

Here's my take.

I doubt it but, if Todd were to loose any low end power with his cam choice he will make up with C.I.'s.

Basicly if Todd makes for example 650RWHP @ 7k RPM i'm pretty sure he won't be making zero power at 2k or 3k RPM.
I can't wait to see how it turns out.

Pete

Pete,

Todd is taking a methodical/quantitative approach. I'm looking at a similar approach but for a motor configuration that more of us are likely to do.
Your approach, btw, has also been very methodical. I'd like to use some other tools to point toward what the right combo should be.

[tpepmeie]

650RWHP @ 7k RPM I'd love to see that one.
AL.

Yeah, 650 rwhp is a little optimisitc. Fingers crossed for 600, though! :cheers:

Todd

[XfireZ51]

Yeah, 650 rwhp is a little optimisitc. Fingers crossed for 600, though! :cheers:

Todd

Todd,

What are you using to develop camshaft and valve timing specs?

[XfireZ51]

Here's a great article courtesy of our DOHC cousins at SVTPerformance.

http://www.svtperformance.com/forums/new-edge-cobras-51/664268-cam-science-101-beyond.html

[Pete]

Guys emphases on "EXAMPLE".

I know bigger cam could make a lil more power.
Horsepower costs money and i'm a little short at this time.

.239 might not be worth the gains/money over my .236
.242 or .244 could be worth the few ponies
If a set of SGC Stage III intakes come up for sale for the right price i'll be all over them like a cheap suit.
It's on my to do list for the near future.:)

Pete

[tpepmeie]

Todd,

What are you using to develop camshaft and valve timing specs?

I just write the checks, Dom, and let the professionals do it. :) Finding someone you trust to do the cam design is half the battle. I have a simple formula using stroke length and RPM I use to get ballpark duration, which is where I pulled Pete's numbers from. Lift is a function of valve size to cylinder size and RPM.

I told my guy that he might sell 6-8 sets a year if these billets work, and if he offered a range of designs. I think the price point would have to be sub-3000 to get that much volume. The cams really need to be tailored to your airflow and hp targets, but a few "off the shelf" designs would satisfy most owners.

[Bob G]

Dom heres some ford cam specs
http://www.crowcams.com.au/media/catalogues/27.0%20FORD%20BA8.pdf

[XfireZ51]

Todd,

Thanks for that.

Bob,

I'd actually seen similar charts on some of the Ford sites I visited yesterday as I searched for info. I'll see if I can find them again. Of course we are talking about a smaller displacement motor but it helps provide some perspective.

[scholtmj]

ported LT5 heads have 255cc intake port and 340cfm

.

What lift is this at?

[Pete]

What lift is this at?


.450

Pete

[scholtmj]

Try to get .020" more lift anyways, past where they turn the corner, if you can.

Assuming 340cfm @ .450 is peak flow; according to flyin's suggestion stage III cams w/.450 lift could be improved upon.

[Pete]

Assuming 340cfm @ .450 is peak flow; according to flyin's suggestion stage III cams w/.450 lift could be improved upon.



Let me say flowbench's are like rwhp dyno's
I have seen too many variances.

That said, yes i would like to try Stage III intake cams.
Sooner or later i will try them, all it takes is money
I would love to see 130+MPH from a stock bottom end 350ci

HP is like Sex and Money can never have enough.:)
Pete