Pick me a cam

Posted By: 1_WILD_RT

Pick me a cam - 02/21/13 03:26 AM

I'm playing around with the idea of a cam swap in my Challenger, nothing big just hoping to optimize what I have..

The Car...
!970 Challenger R/T Vert.. Heavy probably 3700lbs
3.23 gear which is staying, this is a highway cruiser not a hotrod
727 with stock convertor currently it with flash 2200ish
Stock exhaust manifolds to tips
Stock A/C, going to change to a Sanden compressor

The Engine...
Original 383 with 75K miles since O/H
.030 O/S KB 162 pistons .018 in the hole 5cc valve trough
with the current 906 heads C/R is around 8.2-1
But I'm changing to a set of 915 heads which have been cut .030 which reduced chamber volume to 76cc
New C/R should be 9.7
Current cam is the OE Resto cam
Intake is a Performer RPM & Carb is a Holley 4776 600cfm D/P
I've jetted it down four sizes & opened the PVCR's

I know the official stance is a heavy car with tall gears should have a vacuum secondary carb but it runs well & I accept the fuel mileage.....

So lets hear your thoughts...

Posted By: MLR426

Re: Pick me a cam - 02/21/13 03:30 AM

Quote:

I'm playing around with the idea of a cam swap in my Challenger, nothing big just hoping to optimize what I have..

The Car...
!970 Challenger R/T Vert.. Heavy probably 3700lbs
3.23 gear which is staying, this is a highway cruiser not a hotrod
727 with stock convertor currently it with flash 2200ish
Stock exhaust manifolds to tips
Stock A/C, going to change to a Sanden compressor

The Engine...
Original 383 with 75K miles since O/H
.030 O/S KB 162 pistons .018 in the hole 5cc valve trough
with the current 906 heads C/R is around 8.2-1
But I'm changing to a set of 915 heads which have been cut .030 which reduced chamber volume to 76cc
New C/R should be 9.7
Current cam is the OE Resto cam
Intake is a Performer RPM & Carb is a Holley 4776 600cfm D/P
I've jetted it down four sizes & opened the PVCR's

I know the official stance is a heavy car with tall gears should have a vacuum secondary carb but it runs well & I accept the fuel mileage.....

So lets hear your thoughts...

XE268H Comp, Wide power band and a great sound

MLR426

Posted By: Pacnorthcuda

Re: Pick me a cam - 02/21/13 03:35 AM

From the VooDoo line I would say a 60302

Posted By: RoadRunnerLuva

Re: Pick me a cam - 02/22/13 03:00 AM

Quote:

From the VooDoo line I would say a 60302

with Pacnorth....this cam would work
well with your combo IMO....makes good power
from 2000-5500 rpm.

Posted By: Dunnuck Racing

Re: Pick me a cam - 02/22/13 03:10 AM

I agree with MLR
A much better choice than the Voodoo cam suggested. The 60302 is not going to do anything your current cam doesn't already do. :twocents
Keith

Posted By: MLR426

Re: Pick me a cam - 02/22/13 03:24 AM

Quote:

Quote:

From the VooDoo line I would say a 60302

with Pacnorth....this cam would work
well with your combo IMO....makes good power
from 2000-5500 rpm.

XE268H Comp Has a wider operating band than the Voodoo

MLR426

Posted By: Mebsuta

Re: Pick me a cam - 02/22/13 07:32 AM

I don't know. Relative to other cams its size, the OE resto cam has late intake valve closing, early exhaust opening. In theory, I think you need pretty high compression, and it kind of lends itself to high rpm operation in 383.

I use it. It's trouble-free but not spectacular. If I try another, I will use something that closes intake sooner and traps more cylinder pressure, like old single-pattern Comp 268H or Erson tq20h, or a copy of something like that.

Well, since you are changing to closed chamber heads, see what it does with increased compression before you change cams.

Posted By: Junky

Re: Pick me a cam - 02/22/13 05:57 PM

W.H.I.P.L.A.S.H. Here's a cam for ya!

Posted By: GTX MATT

Re: Pick me a cam - 02/22/13 06:06 PM

Mopar .455 272/272

Posted By: 1_WILD_RT

Re: Pick me a cam - 02/22/13 06:13 PM

Quote:

W.H.I.P.L.A.S.H. Here's a cam for ya!

I'm leaning toward the Comp, I've run it before in a smallblock & it's a strong choice.... I was hoping someone might post a wildcard choice just cause I like to be different...

The Whiplash isn't an option, I've got to high of C/R to consider it.. straight from Hughes website.. ""These are killer cruising cams made for low compression (8:1-8.75:1) engines and are designed so the cylinder pressure will not be reduced (Torque Killer!) like other cams of this size or type. " I'm gonna be a full point higher which means my cylinder pressure would be well into the detonation zone....

Posted By: patrick

Re: Pick me a cam - 02/22/13 06:18 PM

Quote:

Quote:

From the VooDoo line I would say a 60302

with Pacnorth....this cam would work
well with your combo IMO....makes good power
from 2000-5500 rpm.

X3.....yes this cam has less .050 duration than the XE268, but it probably has similar .2" duration, for similar max power potential, while having an earlier intake closing point for more cylinder pressure and low RPM torque. the slightly wider lobe separation will also keep the torque curve flatter, and carry the HP high enough for most street hooliganing (~5500 RPM)

personally, I think most people overcam their cars....

Posted By: Dunnuck Racing

Re: Pick me a cam - 02/22/13 06:28 PM

I have used whiplash cams with some real good results,and I agree its not quite right. I would avoid the MP 455 and the Voodoo suggested simply because they have a pretty wide lsa for what you have. Makes them idle smoother and have better vacuum but with the duration you will be running it wont be an issue.
The Comp is a little better,slightly narrower lsa for a similar duration but not so narrow that it will have a very rough idle and be hard to live with.
One other option is a Lunati Street Master 225/225 at .050 with 477 lift and a 108 lsa. I run one in my tow rig 440 and it helped it make some serious torque which is what you need with a heavy car and not much gear.
Keith

Posted By: patrick

Re: Pick me a cam - 02/22/13 09:16 PM

Personally, I prefer wider LSA's, it sacrafices a little bit of peak torque in exchange for more torque above the torque peak, so for a given duration, your powerband will be wider, and your torque curve flatter.

I also like short duration, high lift cams. the XE268 is a .842" lifter lobe profile, but a very aggresive one.

as a comparison, Bullet Cam's most aggressive .842" 226@.050 lobe is 270 adv, 226@.050, and 138@.2" with .326" lobe lift (.489 with 1.5 rockers)...

their most aggressive .904" lobe with the same 226@.050 duration is 270 adv, 226@.050, and 142@200 duration with .335" lobe lift (.502" lift with 1.5 rockers, 4 degrees more duration over .2" lobe lift)

and their least aggressive 226@.050 .842" lobe is 274adv, 226@.050, 127@.2, and .273" lobe lift....

so...to get similar .2" durations as the aggressive .842 lobe with a .904 lifter lobe, you can drop .050 duration down to 220@.050, or to the less aggressive .842 lobe, you can drop your .050 duration down to 212-214 degrees

http://bulletcams.com/Masters/Hlobes.htm
http://bulletcams.com/Masters/HClobes.htm

I had an XE262 in a 360 running about 8:1, and it wasn't bad, but it was a little cranky at low speed, and idle was a bit more radical than I would have liked. that was with a MP166K converter, low gear 904 and 3.55's....don't think I'd want bigger than that in a daily driver/cruiser, personally.

Posted By: Dunnuck Racing

Re: Pick me a cam - 02/22/13 09:42 PM

The wider lsa / peaky torque curve idea is nothing more than a common misconception . I have proven it is a myth on several different builds as have several other people.
A lot of guys still believe intake closing points are the main thing to look at too,but that is 80's technology being passed down.
I just tested a few different cams with the intake closing point being nearly identical , moderate duration,and varying lsa in a mild 360. The best overall torque curve was the narrowest lsa

Keith

Posted By: GTX MATT

Re: Pick me a cam - 02/22/13 10:30 PM

Quote:

The wider lsa / peaky torque curve idea is nothing more than a common misconception . I have proven it is a myth on several different builds as have several other people.
A lot of guys still believe intake closing points are the main thing to look at too,but that is 80's technology being passed down.
I just tested a few different cams with the intake closing point being nearly identical , moderate duration,and varying lsa in a mild 360. The best overall torque curve was the narrowest lsa
Keith

Keith,

Do you think that as the duration grows relative to the displacement and overall aggressiveness of the build that a wider LSA will become more beneficial, assuming the same intake closing point? If you take a stock low performance .430 lift big block cam and change the LSA from 115 to 108 (I know you cant change LSA, but theoretically) I would think it would wake it up a lot merely because it would provide the engine with more overlap, and the overlap on that cam is so low. Take, for example, a 440 that had a single plane intake, headers, and a larger carb and head work. The thing would probably work best with an insanely tight LSA to compensate for the insane lack of duration.

Take a 509 cam and stick it in a 383 that's 100 percent stock otherwise and tightening up the LSA would kill it even more. Open it up and you'd likely see better overall performance due to the fact that now the thing isn't choking so much on the low end, and it didn't have the capacity to work the 509 on the top end with a 108 LSA. (Mopars theory on those new turdy 114 LSA cams since everyone complains the old school ones are doggy in stockish setups)

Posted By: BSB67

Re: Pick me a cam - 02/22/13 10:33 PM

Quote:

The wider lsa / peaky torque curve idea is nothing more than a common misconception . I have proven it is a myth on several different builds as have several other people.
A lot of guys still believe intake closing points are the main thing to look at too,but that is 80's technology being passed down.
I just tested a few different cams with the intake closing point being nearly identical , moderate duration,and varying lsa in a mild 360. The best overall torque curve was the narrowest lsa
Keith

What exhaust in your test, and was moving only the LSA around the changes you made?

Posted By: dogdays

Re: Pick me a cam - 02/22/13 11:13 PM

Crower HDP271.
R.

Posted By: firefighter3931

Re: Pick me a cam - 02/22/13 11:23 PM

Quote:

Crower HDP271.
R.

Bingo !

Perfect cam for a mild 383 using ex manifolds.

Posted By: dogdays

Re: Pick me a cam - 02/22/13 11:27 PM

Actually Crower calls it the 271HDP, I got the numbers and letters mixed up.
222/234@ 50 lift, 112 LSA
R.

Posted By: goldmember

Re: Pick me a cam - 02/22/13 11:29 PM

Quote:

The wider lsa / peaky torque curve idea is nothing more than a common misconception . I have proven it is a myth on several different builds as have several other people.
A lot of guys still believe intake closing points are the main thing to look at too,but that is 80's technology being passed down.
I just tested a few different cams with the intake closing point being nearly identical , moderate duration,and varying lsa in a mild 360. The best overall torque curve was the narrowest lsa
Keith

We knew in the 80's(I'm sure others in the 50's did as well) the easy way to kill torque and hook a car up was to stretch the lobe centers. Car was a turd but easy to hook. Sticky tracks you'd better get out of the way or put the right cam back in it. I agree also that the wide lsa (broader power band)believers are way off track. Now if you must have 20"idle vac and run a tiny engine in a heavy car,yadda,yadda and don't know a strong performer you'll be happy with your results.With modern induction systems the cam requirements are not what the old tech stuff might prefer. As far a hyd cams go I am not a big fan of any .904 lifter stuff unless your RPM limited by some part of the build. The numbers on the cam tables are not what the engine will see when the hyd lifter gets confused.

Posted By: dogdays

Re: Pick me a cam - 02/22/13 11:35 PM

And here I would probably use a 110LSA custom grind to give it a tad more midrange, the intake duration isn't that big.

I have been reading the hotrod rags for decades and some interesting things are coming out now that there are dynos on every streetcorner. One of those things is the narrower LSA usually makes more power. Narrowing the LSA and keeping the intake valve closing point the same will put the exhaust events later, right? Or am I hallucinating because it's friday afternoon?
Keith, please expand on your last comment.

R.

Posted By: Dunnuck Racing

Re: Pick me a cam - 02/22/13 11:49 PM

As soon as I can sit down and type some info out I will. It seems every time I test something and write an article,and send it off,the subjects pop up on here!
I hate to give away all the information I just submitted as an article since it makes people care less about the article later.
A good example is this subject along with the manifolds being talked about on this forum.
Heck,I have been biting my tongue on a couple subjects on this forum for several months because of articles I wrote about six months ago just hitting the stands today.
Anyway,Im out of the shop today. When I get back to town later Ill see how much info I can leak out without giving everything away for now.
Keith

Posted By: Triggerfish

Re: Pick me a cam - 02/23/13 04:51 AM

Engle AMC grind K-54 or split duration K-54-56.

Posted By: Mebsuta

Re: Pick me a cam - 02/23/13 05:30 AM

I guess I need to call Isky. Anything greater than a 108 LSA and I'll be laughed out of Sonic Happy Eating.

Posted By: willard

Re: Pick me a cam - 02/23/13 06:22 PM

Quote:

Quote:

W.H.I.P.L.A.S.H. Here's a cam for ya!

I'm leaning toward the Comp, I've run it before in a smallblock & it's a strong choice.... I was hoping someone might post a wildcard choice just cause I like to be different...

The Whiplash isn't an option, I've got to high of C/R to consider it.. straight from Hughes website.. ""These are killer cruising cams made for low compression (8:1-8.75:1) engines and are designed so the cylinder pressure will not be reduced (Torque Killer!) like other cams of this size or type. " I'm gonna be a full point higher which means my cylinder pressure would be well into the detonation zone....

Thats/ intresting as I enquired Hughes about my 383 with 10.4:1, source heads, stock intake/exhaust, his stall mopar vert, 3.55 rear and they said it would be fun and go for it...

Posted By: Dunnuck Racing

Re: Pick me a cam - 02/24/13 12:54 AM

Willard,
Your aluminum heads are what makes the difference they are better suited for the compression.
Keith

Posted By: Dunnuck Racing

Re: Pick me a cam - 02/24/13 04:04 AM

Sorry it took me a while to expand on things. I usually willingly give out any and all information . Since I just sent in two articles that cover a couple of topics on here,they wont reach the stands for a few months.
So as not to make the articles worthless to the publisher,I need to not give away too much of it so Ill be brief.
I started the cam testing on this 360 a set of cheap 1 5/8" headers. I tests a few cams of similar size . One was a dual pattern,one was a single pattern both with the same basic intake lobes. Then I ttested a cam with the same intake closing point,but was split pattern with a narrower lsa.
After seeing how things acted,I went back and repeated the testing with manifolds and a couple different header designs.
On this engine ,a basic small block,and sseveral other combinations I have spent a lot of time on,they all made more peak torque and had wider power bands with narrow lsa cams compared to similar cams with wider lsa.
I will be the first to admit,I have not worked with every combination possible.
Most Mopar small and big blocks favor narrow lsa cams,and Im not the only guy that thinks so.
MOST cam companies spread the lsa out a couple degrees over optimum to help with idle and vacuum on a lot of their " performance" cams because they feel we will pick a cam with too much duration .
Keith

Posted By: dennismopar73

Re: Pick me a cam - 02/24/13 04:07 AM

Quote:

I'm playing around with the idea of a cam swap in my Challenger, nothing big just hoping to optimize what I have..

The Car...
!970 Challenger R/T Vert.. Heavy probably 3700lbs
3.23 gear which is staying, this is a highway cruiser not a hotrod
727 with stock convertor currently it with flash 2200ish
Stock exhaust manifolds to tips
Stock A/C, going to change to a Sanden compressor

The Engine...
Original 383 with 75K miles since O/H
.030 O/S KB 162 pistons .018 in the hole 5cc valve trough
with the current 906 heads C/R is around 8.2-1
But I'm changing to a set of 915 heads which have been cut .030 which reduced chamber volume to 76cc
New C/R should be 9.7
Current cam is the OE Resto cam
Intake is a Performer RPM & Carb is a Holley 4776 600cfm D/P
I've jetted it down four sizes & opened the PVCR's

I know the official stance is a heavy car with tall gears should have a vacuum secondary carb but it runs well & I accept the fuel mileage.....

So lets hear your thoughts...

I would not go over a 270h comp cam ,keep the the c/l @ 105,108 install at @ 102
Watch your push rod lenghts as they can be to short for a hyd situation?
Not much diff in your assumed comp pick up.
a little short on carb JMO

Posted By: MLR426

Re: Pick me a cam - 02/25/13 02:41 AM

Quote:

Quote:

I'm playing around with the idea of a cam swap in my Challenger, nothing big just hoping to optimize what I have..

The Car...
!970 Challenger R/T Vert.. Heavy probably 3700lbs
3.23 gear which is staying, this is a highway cruiser not a hotrod
727 with stock convertor currently it with flash 2200ish
Stock exhaust manifolds to tips
Stock A/C, going to change to a Sanden compressor

The Engine...
Original 383 with 75K miles since O/H
.030 O/S KB 162 pistons .018 in the hole 5cc valve trough
with the current 906 heads C/R is around 8.2-1
But I'm changing to a set of 915 heads which have been cut .030 which reduced chamber volume to 76cc
New C/R should be 9.7
Current cam is the OE Resto cam
Intake is a Performer RPM & Carb is a Holley 4776 600cfm D/P
I've jetted it down four sizes & opened the PVCR's

I know the official stance is a heavy car with tall gears should have a vacuum secondary carb but it runs well & I accept the fuel mileage.....

So lets hear your thoughts...

I would not go over a 270h comp cam ,keep the the c/l @ 105,108 install at @ 102
Watch your push rod lenghts as they can be to short for a hyd situation?
Not much diff in your assumed comp pick up.
a little short on carb JMO

The 270H COMP is what I use for stock hp 440 resto builds.

MLR426