Cam recommendations seem to light to me? What am I missing.

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Cam recommendations seem to light to me? What am I missing.

Post  paperman on April 28th 2016, 12:36 pm

I sent a inquiry for a camshaft to a couple grinders. I filled in the sheets with all the info. Basics are 4.5 stroke, 6.7 rod, 30 over, A429 heads cleaned up, Icon 10:1 pistons. F350, 4x4 C6 42" rubber, 5.13 in both ends. Victor intake, Domy carb, 2.125-4" headers.

They came back with what looks like a very soft cams. There are 4 different recommendations, here are 2 of them:
Duration @ .050 = 245/250
Lift = .576/.571

Duration @ .050 (Int/Exh): 233/241
Gross Valve Lift (Int/Exh): .564/.582

This seems to be fairly small for 545 inches. My last 466 used the C460 cam from FMS and I really liked it. I want to stay hydraulic flat as this is driven a fair amount.

Do these seem inline with what I am asking for or are they out in left field? I was expecting more in the mid .600's.


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Re: Cam recommendations seem to light to me? What am I missing.

Post  JBR-3 on April 28th 2016, 5:31 pm

42" tires with 5.13 gears are roughly the same as 27" tires with 3.25 gears.
And F350's are not lightweight.
Hope this helps.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  paperman on April 28th 2016, 5:49 pm

Kinda, most run the low side of the Tcase at a 2.69:1 reduction before it hits the diffs.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  supervel45 on April 28th 2016, 5:57 pm

I would say they are inline for your rig. You don't want to loose all your low end torque and also the A429 heads might not like as much cam as say P51's and larger heads would.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  rmcomprandy on April 28th 2016, 8:04 pm

paperman wrote:I sent a inquiry for a camshaft to a couple grinders.  I filled in the sheets with all the info.  Basics are 4.5 stroke, 6.7 rod, 30 over, A429 heads cleaned up, Icon 10:1 pistons.  F350, 4x4 C6 42" rubber, 5.13 in both ends.  Victor intake, Domy carb, 2.125-4" headers.  

They came back with what looks like a very soft cams.  There are 4 different recommendations, here are 2 of them:
Duration @ .050 = 245/250
Lift = .576/.571

Duration @ .050 (Int/Exh): 233/241
Gross Valve Lift (Int/Exh): .564/.582

This seems to be fairly small for 545 inches.  My last 466 used the C460 cam from FMS and I really liked it. I want to stay hydraulic flat as this is driven a fair amount.  

Do these seem inline with what I am asking for or are they out in left field?  I was expecting more in the mid .600's.    


Valve lift IS a bit soft for those heads; first cam is close on duration ... maybe 3 or 4 more degrees of exhaust duration.

Your collectors are to big unless they are REALLY long.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  paperman on April 28th 2016, 8:10 pm

The collectors proper are only 8" or so, but it is connected straight to a 4' length of 4" pipe with 2-45deg offsets midway.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  supervel45 on April 28th 2016, 8:32 pm

You did not mention torque converter stall speed. It has a lot of bearing on cam choices also.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  paperman on April 28th 2016, 8:41 pm

Dont own a converter for this yet. Trying to get the engine together and see how it feels. My plan was trying to keep stall as low as possible to keep the heat down. With the thick stuff we play in the load on the drive train is huge. In low gear, low range and 5.13 getting RPM's up should not be an issue. I have a giant cooler but we dont run 10 seconds at a time, more 10 minutes.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  69F100 on April 28th 2016, 9:00 pm

supervel45 wrote:I would say they are inline for your rig. You don't want to loose all your low end torque and also the A429 heads might not like as much cam as say P51's and larger heads would.


I am running .708 .712 on my a429 heads but it is a solid lift roller but he running a hydraulic flat tappet so that will limit his lift
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Re: Cam recommendations seem to light to me? What am I missing.

Post  Straubtech on May 6th 2016, 10:38 am

What do you want max HP rpm to be?

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Post  paperman on May 6th 2016, 10:59 am

6000ish. I don't care to spin it to the moon and keep it there as RPM's cost money and maintenance. Not looking for a dyno killer, this is a big play truck that we take out on the weekends to enjoy being outside.

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Re: Cam recommendations seem to light to me? What am I missing.

Post  Straubtech on May 6th 2016, 11:22 am

Ballpark.....

.620/.600
248/260
107

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Re: Cam recommendations seem to light to me? What am I missing.

Post  paperman on May 6th 2016, 11:29 am

I found a Howards in stock, I needed a cam and this is what I settled on. Ill likely look for a better grind in the fall when it comes back out.

241491-10
0.614 int./0.635 exh
232 int./238 exh
110

Engine is together, waiting on new damper spacer as the old one magically walked out of the shop somehow Crying or Very sad Hope to install and break in next weekend, then get to enjoy putting the valve springs back together in the truck cheers

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Re: Cam recommendations seem to light to me? What am I missing.

Post  Straubtech on May 6th 2016, 11:31 am

paperman wrote:I found a Howards in stock, I needed a cam and this is what I settled on.  Ill likely look for a better grind in the fall when it comes back out.

241491-10
0.614 int./0.635 exh
232 int./238 exh
110

Engine is together, waiting on new damper spacer as the old one magically walked out of the shop somehow Crying or Very sad Hope to install and break in next weekend, then get to enjoy putting the valve springs back together in the truck cheers

I'd advance that thing as much as you can, with that much piston speed in here at low rpm and now port velocity she is going to "hunt" for air.

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