Stroker specific cams?

[Cal Tonsley]

Personally with Trick Flows I think I’d be going a bit larger than 232 @ .050”! If you’re going to use power brakes why not have a think about running a vacuum pump! At the end of the day it’s not about whether your engines a stroker or not, it’s all about cubic inches, head flow - resultant RPM and dynamic compression. When I was in the valve train industry some years back we generally calced Int duration for more serious engines based on head flow RPM potential at the given cubes and calced the exh duration based on exh flow percentage of the intake. Ramp speed / stability, lifter diameter and lobe separation were of course all important factors too.
Accepting that there’ll be plenty of good / better, more up to date recommendations but just for fun my recommendation would be a nice stable mechanical street type steel roller cam with an iron gear, approx 242/250 degrees @ .050, .550” int / .575” exh with 1.5 rockers on 110 or maybe even 108 lobe separation. Dial it in so the seat timing @ .004” lift sees the intake close at around 70 degrees ABDC for a DCR of about 7.9:1
Glad to hear your going with the Pro Flo 4 it’s what I’m using on my stroker build as well!

 

[12many]

Like rumbleness said, it's all about the lifter diameter. In other words, the larger the lifter diameter, the more lift per a given duration that lifter can stand. Make sense? Sometimes though there are situations where you actually WANT a Chevy or a Ford lobe on a Mopar camshaft. It's all dependent on what you're doing. Say for instance you're running a large by huge solid roller on the street and you want it to last, rather than wear out the valve springs or the rest of the valve train. In that instance, you're not lookin for every ounce of power. It's probably gonna make a pile anyway, so if you're not racin for money, you want that expensive stuff to last a while, so you choose a lobe that's less aggressive "to a Mopar". Conversely, you may want something that's on the ragged edge of everything in the world and if that's the case, you're probably racing for dough and want to spank everything out there, so you choose the lobe best designed to the Mopar lifter diameter to do that. Chevy especially does not have that advantage, because they cannot stand a Mopar lobe with a ton of lift without ill effects. Mopar has the best of both worlds, because we can pick and choose lobes from any domestic lifter diameter we want to accomplish a given objective. Did any of that make sense?

My post is an example of why its a bad idea to mix adult beverages and forum posting. My user name says it all, but anyway, I'm well aware of lifter diameters and benefits of one vs. another, actually well read at least enough to know how to choose a lobe with specs I'm looking for. I think I just let my dislike of the use of the term "Chevy lobe" get the better of me! Might be defensive cause im running an Isky circle track cam with lobes for a .842" lifter?? LOL Many throw that term around often in a negative way, just don't see it the same, I get it all, I just see lifter diameters, and specs, slow up to fast, not whether its a Chevy lobe, or Ford lobe etc All I can say is its just another inebriated post on my part, apologies for running off the road.

 

[rumblefish360]

@12many LMAO, I think it was a good post topic.
@Cal Tonsley Good post.

 

[mderoy340]

My brother runs a cam spec'd by Brian IMM engines @ou812 and the 408 motor runs the number. The cost was not much more than off the shelf. Sometimes you are better off paying for knowledge from someone with tons of real world experience.

 

[Wyrmrider]

for Bullet (and all of them but last time I talked with Bullet) I had to specify to use the .904 list
then they really went to work to pick a cam
IDK if Jones has non race .904- you can check his recommendation to see if he is using a lobe off the chevy list- or ask him for flat tappett- He'll give you a straight shot
but his timing recommendation will be spot on- he does use head flow
but if chevy lobe recommended you could get a shorter MOPAR lobe with the same or greater area and get additional torque
his roller lobes are the best
and his 256 duration HYD is THE BEST in that class (for you low compression non race builds)
Crower also specify their non catalog lobe list- we do have a good person there
OK 12 I'll use .842 lobe
I was an ISKY WD for years and Ed's first .904 lobe for the Max Wedge really made a winner- for years it was his only .904 lobe except for the hardface Top Fuel stuff
$100 for advice from a pro is well worth it versus getting a "custom" cam from a non expert

 

[yellow rose]

My post is an example of why its a bad idea to mix adult beverages and forum posting. My user name says it all, but anyway, I'm well aware of lifter diameters and benefits of one vs. another, actually well read at least enough to know how to choose a lobe with specs I'm looking for. I think I just let my dislike of the use of the term "Chevy lobe" get the better of me! Might be defensive cause im running an Isky circle track cam with lobes for a .842" lifter?? LOL Many throw that term around often in a negative way, just don't see it the same, I get it all, I just see lifter diameters, and specs, slow up to fast, not whether its a Chevy lobe, or Ford lobe etc All I can say is its just another inebriated post on my part, apologies for running off the road.

Sometimes you have to look at the whole package. If it comes down to it, I'd rather have the bigger lifter with a quicker lobe AND the correct timing. If it comes down to it, I'd take a Chevy lobe with the correct timing rather than a Chrysler lobe with the wrong timing. I hope that makes sense.

And don't apologize. It's much better to hash this stuff out so guys can learn. I've been doing this stuff my entire life and I'm still stunned by the stuff that still gets palmed off as truth when it's just fiction. So discussing the reasons why some of this stuff we say is what we say is always a good thing.

Again, in my world, this is why I don't buy cams off the shelf. Although I should add one of the very best solid cams I ever used was the Isky 1012C. Great cam. But if I can get the Chrysler lobe with the correct timing, I always opt for that. Then you give up less. In the end, I always look at timing numbers first though, because lifter diameter and lobe aggressiveness is not as important as what you timing numbers are. I try and get the best of both.

 

[Wyrmrider]

Exactly right YR

 

[nm9stheham]

As far as the EFI goes, Edelbrock recommends a minimum of 8 inches of vacuum at idle, and have a 3 settings for cam based on duration. It seems fairly forgiving to a point, but I want to keep the duration under 232@.50 for good measure. I am spending some time on their forum to see what other users are running for cams.

What is interesting is Comp uses 114 lobe separation and 8 degree duration separation on the linked cam. I'm not sure if it has more to do with it being a stroker cam, or that the XFI lobes require it. The research continues.

Looking at the proFLo 4 setup instructions, I see that they have a tabulation of 'base maps' numbers. You select the base map before firing up, based on cubes, fuel pressure range, and cam duration range (mild, moderate, or race). You can look this up in the instructions. For 'race' range durations, they list idle vacuums of 5 to 12 in. So not sure how that relates to 8" minimum. So they have tried to account for use of longer duration and narrower LSA cams.

Having said that, this system uses manifold pressure as one of the primary determinants of air flow into the engine, and thus determine load. It is an indirect method..... unlike carb venturis which are actually calibrated and adjusted to real airflow, in essence making them airflow sensors(!). Lower overall MP range is gonna simply give the ECU less resolution to be able to discern as well between different airflows (loads) and so EFI operation is going to be less precise with lower LSA and more ambiguous MP. If you're working mostly at WOT, no big deal. If you are working across a wide range of loads and RPM's then it becomes different deal, and a wide LSA helps to increase the MP range and thus the ability to resolve load/airflow.

It is not a performance matter per se, but a matter of helping the EFI to better manage the AFR's and ignition timing based on the limitations of using MP are a primary determinant of load. How good bad or indifferent it may be for your intended engine use, IDK.

BTW, here is an older Pro-Flo owners manual. If you read it and look at the graphic comparison of short and long duration cams (lower or higher overlap) and how AFR and timing are set, you can get some idea of how the system changes the settings with different MP levels.
http://www.mpair.com/assets/pdf/general/v.belt.tips.pdf

 

[DrEamer]

So, it's been a crazy busy day at work today, and I have not had the time to keep up with all this, I have read it all, but not digested in full. Just to answer the question about where I got the 8 inches of vacuum number, it came from Nate on the Edelbrock forum. My understanding is that he is the tech from Edelbrock directly set up as the moderator. It was his suggestion that it was a safe number. I want more then that anyway to run the brakes. I know I could run other options, but would rather spend my effort elsewhere. Now, for your consideration, Bullet Cams has submitted their cam design. It looks like a good safe bet, which is not a bad thing in my book. here is part of their email below.


Here is a camshaft grind to use for your 408 engine. This will make the vacuum

Needed for the injection. This will also have good sound.

Let me know if you have questions on this.




Thank you,

Chris



Intake

230 @.050”

.367” lobe lift, .587” with 1.6 rocker

284 duration @.006”



Exhaust

234 @.050”

.367” lobe lift, .587” with 1.6 rocker

288 duration @.006”



113 lobe separation

109 intake centerline

 

[j par]

So, I have filled out online cam recommendation forms from Crower, Bullet, and Jones cams. The forms were interesting if nothing else. I found it interesting that Jones and Crower both asked for head flow numbers, but Bullet did not. Then Jones and Bullet asked for spring pressures, but Crower did not. Comp on the other hand asked for neither. I will be interested in see what they all come up with.

My only experience really with ordering cam has been through Oregon cam grinding. I had a purple performance cam in the 318 that came with my car and I blew up the motor. When I had the stroker kit put in an engine put together for me it was recommended to go to have an Oregon cam grind done on my existing cam. I wanted something pretty radical and he was trying to talk me out of it, but I had to have it. With my 1.6:1 rockers it was a little over six hundred lift with a 259 267 duration on a 107 lobe separation. It was exactly what I wanted! Completely radical could barely hold an idol and absolutely no bottom end. You know where it ran like crap so bad that when you took a friend for a drive they weren't sure if you were going to make it back because it ran so rough, but when you got to the straightaway and opened it up they were scared for their lives...
Seeing as how I only live the the 20-mi away I went over and talked to Ken the owner and who I asked for on the phone. We had a discussion on what I was looking for and what I wanted "this time"
I ended up with 238-248. We left the lobe separation low at a 108 to help bleed compression which also made it a one-off cam. (The number profile for this cam has a higher LS) also it list for a 1.5 to 1 rocker, but with my 1.6:1 it's a 526 lift. I have 28 in tires with 354 gears. It pulls right from the bottom end in every gear. Starts and idles perfect. Still lots of hot rod left in it, but also has manners.
My next grind will probably just have more lift...
It's been fun picking one and having the ends of the scale to have the knowledge..
I see absolutely no reason why he couldn't grind absolutely whatever you wanted. Whatever lift, whatever lobe separation, and whatever duration makes you happy.
Charge me $79 to gind my cam and $4 each I think for resurfacing each lifter. I remember it being around or just under $150...
It'll be fun whatever you choose...

 

[yellow rose]

So, it's been a crazy busy day at work today, and I have not had the time to keep up with all this, I have read it all, but not digested in full. Just to answer the question about where I got the 8 inches of vacuum number, it came from Nate on the Edelbrock forum. My understanding is that he is the tech from Edelbrock directly set up as the moderator. It was his suggestion that it was a safe number. I want more then that anyway to run the brakes. I know I could run other options, but would rather spend my effort elsewhere. Now, for your consideration, Bullet Cams has submitted their cam design. It looks like a good safe bet, which is not a bad thing in my book. here is part of their email below.


Here is a camshaft grind to use for your 408 engine. This will make the vacuum

Needed for the injection. This will also have good sound.

Let me know if you have questions on this.




Thank you,

Chris



Intake

230 @.050”

.367” lobe lift, .587” with 1.6 rocker

284 duration @.006”



Exhaust

234 @.050”

.367” lobe lift, .587” with 1.6 rocker

288 duration @.006”



113 lobe separation

109 intake centerline

That cam will peak at 5200-5400 max. If you can get down to 8 inches of vacuum, I don't get the short duration and 113 LSA. You are induction limited and that only hurts mid range power.

 

[nm9stheham]

I am not looking for the ultimate horsepower, but I don't want to leave easy HP on the table as long as it does not hurt drivability.

YR, this is the OP's stated goal for this engine/cam on page 1 of this thread. I'd suspect this has a lot to do with the results... this project/design is not about peak HP.

FWIW..... The other thing about narrow LSA is that it is going to make your lower RPM engine operation less torquey. Yeah, I know, narrow LSA moves the torque peak down and/or extend the higher levels of the torque band down, and it does make the exhaust pull-through work better at 'lower' RPM's.. but 'lower' is all relative and is still up in what I would consider 'mid range' RPM's. Once you go low enough in RPM the exhaust pull through stops and the intake reversion goes up with a narrow LSA, and the torque is gonna drop off the table. That is a reason all of the catalog 'torque' cams have LSA's up on the 112-114 range. If you are running certain forms of engine operation, too narrow on LSA just hurts low RPM operation, regardless of carb or EFI. All depends on what you are doing with the engine.

 

[j par]

YR, this is the OP's stated goal for this engine/cam on page 1 of this thread. I'd suspect this has a lot to do with the results... this project/design is not about peak HP.

FWIW..... The other thing about narrow LSA is that it is going to make your lower RPM engine operation less torquey. Yeah, I know, narrow LSA moves the torque peak down and/or extend the higher levels of the torque band down, and it does make the exhaust pull-through work better at 'lower' RPM's.. but 'lower' is all relative and is still up in what I would consider 'mid range' RPM's. Once you go low enough in RPM the exhaust pull through stops and the intake reversion goes up with a narrow LSA, and the torque is gonna drop off the table. That is a reason all of the catalog 'torque' cams have LSA's up on the 112-114 range. If you are running certain forms of engine operation, too narrow on LSA just hurts low RPM operation, regardless of carb or EFI. All depends on what you are doing with the engine.

I'm sorry I didn't see post 61...

 

[nm9stheham]

That cam will peak at 5200-5400 max. If you can get down to 8 inches of vacuum, I don't get the short duration and 113 LSA. You are induction limited and that only hurts mid range power.

And one other thing FWIW.... I realize that a lot of the thinking about LSA and EFI comes from old experience of putting more radical cams with narrow LSA into a stock EFI system The manifold pressures goes way out of the 'normal' range for which the EFI programming was designed and the engine operation goes haywire. So those experiences color a lot of think and comments; I realize I'm guilty of that here to some extent.

That goes back to how Edelbrock gives you different maps to try to work with the expected manifold pressure ranges. But those maps don't fix the MAP sensor having less resolution, and more ambiguity, for mild engine operation modes with a narrow LSA; that is kinda like having too large a booster venturi in a carb.... proper for high flow operation but not so good for low flow operation.

 

[nm9stheham]

I'm sorry I didn't see post 61...

Not on topic, but when are you going snowmobiling again! Never too early to start planning LOL

 

[j par]

Not on topic, but when are you going snowmobiling again! Never too early to start planning LOL

I tell you what, I'll reopen the snowmobiling Blues thread and not disturb this one anymore about this, but very good thoughts, extremely good thoughs...

 

[j par]

As far as the Cam go's, I can't tell anybody anything but what happened with my personal experience with said cams. I like where I'm at and I know where I want to go if I do change at this point. I believe I have a grasp on the idea. That's my personal experience with a small block Stroker. I don't have any Guru theories on them....

 

[yellow rose]

YR, this is the OP's stated goal for this engine/cam on page 1 of this thread. I'd suspect this has a lot to do with the results... this project/design is not about peak HP.

FWIW..... The other thing about narrow LSA is that it is going to make your lower RPM engine operation less torquey. Yeah, I know, narrow LSA moves the torque peak down and/or extend the higher levels of the torque band down, and it does make the exhaust pull-through work better at 'lower' RPM's.. but 'lower' is all relative and is still up in what I would consider 'mid range' RPM's. Once you go low enough in RPM the exhaust pull through stops and the intake reversion goes up with a narrow LSA, and the torque is gonna drop off the table. That is a reason all of the catalog 'torque' cams have LSA's up on the 112-114 range. If you are running certain forms of engine operation, too narrow on LSA just hurts low RPM operation, regardless of carb or EFI. All depends on what you are doing with the engine.

This is true is the cam timing is wrong. If you get the timing correct, the narrower LSA won't kill the bottom. There are two kinds of reversion. The really bad reversion when the close the intake too late. That's a killer.

Then you have reversion which occurs at overlap. Again, this is where a faster lobe is a big deal.

I can tell you the simple truth is if you are running that much displacement, and you are induction limited, a wide LSA is a killer. It always has been.

That's why I cringe when I see a cam with a 10 degree split and a wide LSA. All that means is the cam is short on duration, and they are blowing the LSA out to make a cam with the wrong timing RPM. That's all.

With today's lobes, you can get the timing correct and the narrower LSA is a huge advantage.

Again, on 340 inches I run 255 at .050, I can idle at 750 comfortably (as I've said before, I never let my stuff idle that slow...it's not a Toyota) and carry 9 inches of idle vacuum with a 105 LSA.

Modern lobes are a big deal. That's why several of us on here point it out so often. You don't have to compromise.

 

[Wyrmrider]

Just saying- I have to read the posts
but
LCA is a RESULT not an INPUT
get your Intake and exhaust seat open and closed points and LSA and overlap just magically appear
IMHO overlap needs close watching with EFI
if the overlap and LCA look wrong when the results are in take another look
then note what the .050 numbers are so you can time the cam
If solid we are adjusting seat timing for lash

 

[yellow rose]

Just saying- I have to read the posts
but
LCA is a RESULT not an INPUT
get your Intake and exhaust seat open and closed points and LSA and overlap just magically appear
IMHO overlap needs close watching with EFI
if the overlap and LCA look wrong when the results are in take another look
then note what the .050 numbers are so you can time the cam
If solid we are adjusting seat timing for lash

Exactly. The LSA is a result of event timing. You can fudge a bit...maybe 2 degrees but after that, you are changing the timing.

That's why I say the events have to be correct. And lobe aggressiveness in most cases is important if you know what you want.

Usually when the LSA looks wide to me, you can see the duration is too little for the displacement/RPM/induction/application and you end up moving the timing around. Like I said...that's why the big duration splits almost always end up with a wider than needed LSA...to extend the RPM range because of lack of duration.

 

[Wyrmrider]

I'm with you YR
I usually spec a cam starting with the intake closed point with some logic similar to our long winded poster
However on this EFI build (I have only stock Mopar, Ford and chevy experience and Hilborns) I would start with the amount of overlap required/ allowed
which is also vaccuum
Then figure Intake Open and Ex closed points and move them around some and see what happens keeping the target overlap max (intake and ex considerations)
Once I get a good grip on those then work backward from the Intake open to the Intake closed point and see how big a seat timing I can come up with
ditto on the exhaust, opening as late as possible
Then try lobes that fit to get the most area under the curve on the intake- most flow during the last half of the intake stroke as possible- given heads, ex, etc
I'm going to end up with a shorter cam with more lift and if I have big lobes I'm going to end up with the LCA spread to hold the overlap down
at least that's what I think I will come up with
good camgrinders have already gone through this drill
Note this drill is almost opposite of a THUMPER design where you let the overlap float to a high number to get a big lobe with a reasonable intake closed point (or IMHO unreasonable)

 

[dart19666]

Sorry I have been busy with Street outlaws starting again, Dragweek, and engine masters around the corner I have not look here in a while. I do work for Crower and if you need anything please just ask. Shane@Crower.com and 619 690 7807 desk number.

 

[Wyrmrider]

Thanks for posting Shane
you have to be more up to date of aftermarket EFI than I am
If I'm wrong I'm here to learn
I get enough flack from some members here- I take it as a heads up"

BTW I think would check out
New Page 1
There was a great video on the Crontrolled Induction site but evidently moved to Maxrace- also home of Pipemax
With the controlled induction software you can generate a shape file for a CNC grinder - your very own lobes for your build
or ask Mike Jones Jones cams


comment on my post above- I would start with split overlap
agree with YR on the exhaust extra duration then needing more LCA
start with the events
Maybe PIPEMAX to figure your exhaust "5th cycle" to help pick you IO and EC
My observation is from a different point of view than YR's
the wide lca is a kludge (and maybe necessary) to make up for more intake and especially exhaust duration than necessary- to cut down overlap
so look at it both ways while we explore EFI stroker cams
with closed exhaust how much exhaust pull on the intake do you get and can you cut it off earlier than with open headers? do you need that long exhaust with closed exhaust and what's the tradeoff with the EFI requirements/ vaccuum

 

[DrEamer]

Well this is interesting, Mike Jones has sent me this email recommendation below. Very different then Bullet.

Here's what I recommend
Cam# Chr360M, HR73353-110
233/233 @.050"
.353"/.353" Lobe Lift
110 LSA

 

[yellow rose]

Well this is interesting, Mike Jones has sent me this email recommendation below. Very different then Bullet.

Here's what I recommend
Cam# Chr360M, HR73353-110
233/233 @.050"
.353"/.353" Lobe Lift
110 LSA

Is that a hydraulic roller or a SFT?