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Ideal street cam in my carb'd Magnum vs EFI? #2499548
05/23/18 04:22 PM
05/23/18 04:22 PM
Joined: Jul 2011
Posts: 817
Eugene, Oregon
Secret Chimp Offline OP
super stock
Secret Chimp  Offline OP
super stock

Joined: Jul 2011
Posts: 817
Eugene, Oregon
I'm looking to upgrade my Magnum 318's cam. I am going to keep my 3.23 gears and keeping it mostly "hot street," so I want to find something that won't kill my bottom
end.

The stock motor is pretty fun in the middle, but it's got no guts on either end of the power band right now. It's in a 4000-something pound wagon with 255 rear tires.

Specifically, I'm curious if I could go slightly larger than the upgrade cams that Hughes suggests for computer-controlled Magnum engines, since I've already gotten rid of the OE intake, TB and exhaust manifold restrictions.

They suggest the following cams for 318s and 360s as no-tune-required upgrades:
http://www.hughesengines.com/Index/produ...mp;partid=30226 (318)

http://www.hughesengines.com/Index/produ...mp;partid=30226 (360)

My Magnum has an air-gap intake and 625cfm carb with Doug's midlength headers. Would I benefit from stepping up to the 360-size cam, or will that just move torque away from where I want it? Does anybody still do regrinds that would be a better value for me?

For springs and lifters, I am either getting Hughes' upgrade kit or the 3100/2.2 setup that others use, I'm not sure what is best for my application. I am using Sealed Power's improved-oiling lifters, I am not going to spin this thing high or often enough for Rhodes or fast-bleeddown-type lifters to be worth the extra money.

I'm sure I'd be happy with their 318 steamroller cam, but I'm wondering if I can goose a little more out of my engine vs a factory-EFI 318. If anyone with an upgraded Magnum is local to me within an hour and a half or so, I'd appreciate getting an in-person take.


1967 Dodge Coronet Deluxe station wagon

1.03" T-bars, QA1 arms/rods, Cordoba/GM Metric/Volare brake & knuckle, XHDs, Hellwig rear sway, 318 Magnum w/ air gap, 727, 3.23s
Re: Ideal street cam in my carb'd Magnum vs EFI? [Re: Secret Chimp] #2499599
05/23/18 06:05 PM
05/23/18 06:05 PM
Joined: Jul 2006
Posts: 619
nj
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JAMESDART Offline
mopar
JAMESDART  Offline
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nj
I have been wondering if anyone was using that steamroller. I started thinking about it for my jeep

Re: Ideal street cam in my carb'd Magnum vs EFI? [Re: Secret Chimp] #2499611
05/23/18 06:44 PM
05/23/18 06:44 PM
Joined: May 2003
Posts: 15,487
Florida
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scratchnfotraction Offline
I Live Here
scratchnfotraction  Offline
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Joined: May 2003
Posts: 15,487
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I run a Hughes 5.2/318 whiplash roller cam in my 85 stepside truck.

86 pre-magnum LA roller cam 318, I used comp 901-16 springs.

very happy with this cam as my daily driver the last few yrs.

I also have a Hughes 440 whiplash cam in my 88-440 truck, now this one turned my bone stock 78 RV 440 into a nasty sounding street monster.

750cfm
holley STREET dominator intake
headers/3" pipes/muffs
727-stock low stall TC
8 3/4-2.76 gear 3.23 gear 3.91 gear gets 10-12 mpg
29x15x15 M/Ts
points dist with mech advance locked out 0* and set 32* total

idles through town in 3rd gear, 1000 rpm, 25 mph sounding like a funny car.
red light to red light in town is awesome.
cruz 45-80 down the interstate/hwys like a normal daily driver
drops down in passing gear and shifts out at 75 mph and climbs to well over 125+

I just rolled 11,000 miles on it last weekend on a 250 mile round trip.

only NEGITIVE on the 440 whiplash is 10 MILES to the GALLON! but the smile factor pulling up at a crowded gas pump is awesome.

Hughes said there are better more faster cams to choose from but this one is for the low budget gear head with a mid 80s bone stock lopo smogger mopar.

did I mention the Hughes whiplash cams?

Re: Ideal street cam in my carb'd Magnum vs EFI? [Re: Secret Chimp] #2499619
05/23/18 06:59 PM
05/23/18 06:59 PM
Joined: May 2003
Posts: 15,487
Florida
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scratchnfotraction Offline
I Live Here
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Joined: May 2003
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Florida
here is my pre-magnum LA roller cam 318 combo in the 85 stepside.

stock 91 tbi 318 JY special 300$

holley 650cfm double pumper spredbore carb
holley STREET dominator intake
5.2 whiplash roller cam/comp 901-16 springs/retainers/stock roller lifters
headers/2.5 pipes/muffs
727-low stall TC
8 3/4-3.55-235/75/15

made a nice 318 daily driver that had a lumpy idle and get 18+ mpg

although I am happy it is not as aggressive as the 440 whiplash I hope that the 5.9 whiplash is going to be a lot more aggressive the 360 headed 318.

the magnum 360 whiplash made over 400 HP with efi/tunner so diling in one with a carb should yield good results.

IMHO, if you do a magnum use the Hughes magnum head spring to match the cam profile.

Re: Ideal street cam in my carb'd Magnum vs EFI? [Re: Secret Chimp] #2499621
05/23/18 07:06 PM
05/23/18 07:06 PM
Joined: May 2003
Posts: 15,487
Florida
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scratchnfotraction Offline
I Live Here
scratchnfotraction  Offline
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Joined: May 2003
Posts: 15,487
Florida
my 88-360head 318 police engine

holley 650cfm vac
edelbrock RPM air-gap
hughes 5.9 whiplash roller cam
headers/2.5 pipes/muffs
727 stock high stall TC
8 3/4-3.91sg 275/15/15

Re: Ideal street cam in my carb'd Magnum vs EFI? [Re: scratchnfotraction] #2499677
05/23/18 09:07 PM
05/23/18 09:07 PM
Joined: Jul 2011
Posts: 817
Eugene, Oregon
Secret Chimp Offline OP
super stock
Secret Chimp  Offline OP
super stock

Joined: Jul 2011
Posts: 817
Eugene, Oregon
I don't think that Whiplash-style cams are going to work well with my motor. It's from a 99 Jeep Grand Cherokee and has great, even compression - those Whiplash cams are designed to boost cylinder pressures in emissions-era motors IIRC.

Last edited by Secret Chimp; 05/23/18 09:07 PM.

1967 Dodge Coronet Deluxe station wagon

1.03" T-bars, QA1 arms/rods, Cordoba/GM Metric/Volare brake & knuckle, XHDs, Hellwig rear sway, 318 Magnum w/ air gap, 727, 3.23s
Re: Ideal street cam in my carb'd Magnum vs EFI? [Re: Secret Chimp] #2499879
05/24/18 10:16 AM
05/24/18 10:16 AM
Joined: May 2003
Posts: 15,487
Florida
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scratchnfotraction Offline
I Live Here
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Joined: May 2003
Posts: 15,487
Florida
but that is just it. I talked to Hughes and they said it is for the stock magnum 5.2 or the 5.9 but a tunner is used as it does not play well with the stock pcm.

they also said they have not used the magnum whiplash cams in any pre-magnum roller cam 5.2/318 tbi engines or carbed LA engine.

they would also NOT recommend me using the comp 901-16 springs and was not sure if the hughes LA spring would work with the heavy roller lifters.

there is a member here on the board that has his DAK 5.9 set up with the whiplash roller cam and is bad azz for a stock 5.9
also vids on a dyno with over 400 hp IIRC

I was running a lunati voodoo roller cam for the magnum engine, I looked up a single spring with the same specs as the lunati double springs. = comp 901-16 save $ on machine work/retainers/seals 901s are single with damper/a drop on replacment with out R&R the head/use stock seals/retainers

I was happy with it but stock smooth idle I was not happy with...I was expecting more of an aggressive idle from the hype on the voodoo

looked at the hughes whiplash magnum roller cams and noticed it was almost exact specs as the voodoo roller.

talked to hughes and they would not coment on the voodoo and whiplash being close/copys with some spec changes for the lumpy idle.

so I rolled the dice with the 5.2 whiplash roller, used comp 901 springs. stock roller valve gear in a JY 91 318.

works like a champ. pulls right to 5500 rpm, no valve float, woke the 318 right up for traffic in a daily driver truck.

mind you I have had it in 3 different pre-mag roller cam 318s now 5 yrs time. all do to very high mileage on the used JY engines.

that's why I feel comfortable rolling the dice on the 5.9 whiplash in my pre-mag roller cam 360 headed 318.

magnum 5.2/5.9 use the same head and have the same 9.0 to 1 comp ratio
85-91 pre-mag roller cam 318/360 have the same 9.0 to 1 comp ratio

so any more than that I would agree it wont work well. as per hughes as well.

call them up and tell them what you want to do with your combo and get a recommendation from them.







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