Mopar perf. .620 solid cam spring rates
#2749959
03/07/20 08:07 PM
03/07/20 08:07 PM
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Joined: Nov 2004
Posts: 1,601 Hatfield,Pa.
bigD
OP
top fuel
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OP
top fuel
Joined: Nov 2004
Posts: 1,601
Hatfield,Pa.
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Haven’t been here in along time,does anyone know the required spring rates for MP p4349268 .620 mechanical cam. They say to use the p4876064 springs but don’t show any spring rates,just max. Lift. Thanks
2015 Chrysler200s,2008 Charger R/T R&T,1999 Dakota R/T,1999 Viper ACR,1968 Charger R/T.
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Re: Mopar perf. .620 solid cam spring rates
[Re: bigD]
#2750020
03/08/20 12:26 AM
03/08/20 12:26 AM
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Joined: Aug 2003
Posts: 43,161 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,161
Bend,OR USA
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I don't know the pressures called for on that cam or on those valve springs either but I have a customer who had one of those cams in his bracket motor that I worked on. He broke a valve and bought a new set of 440 source heads instead of fixing the broken 440 Source head. I think that I ended up setting the seat pressures between 140 to 150 lbs. and between 350 and 360 opened and had right at .080 to .100 travel to coil bind. I shoot for .050 to .060 from coil bind on aluminum heads with roller cam valve springs, not so much on the pressure but more focus on the coil bind clearances, that has worked well on a bunch of Mopar BB wedge bracket race motors I've built I use to shoot for 225 Lbs on the seats but now I look for between 250 to 325 lbs. on the seats and from 680 lbs. opened to 840 lbs. open, depending on the cam grind, lobe design and intended shift RPM
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Mopar perf. .620 solid cam spring rates
[Re: Cab_Burge]
#2750024
03/08/20 01:01 AM
03/08/20 01:01 AM
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Joined: Nov 2004
Posts: 1,601 Hatfield,Pa.
bigD
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OP
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Joined: Nov 2004
Posts: 1,601
Hatfield,Pa.
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Thanks Cab I’m going to be using a set of CnC ported stealths i picked up.(new in the box never ran) Hughes built them,but I have no idea of what springs are on them,they do however have 10* retainers and locks which to me would indicate a high spring rate. I’m going to take them to my machine shop and have them checked out so i know exactly what is on them. The specs you gave me are pretty close to what i have found searching around. D
2015 Chrysler200s,2008 Charger R/T R&T,1999 Dakota R/T,1999 Viper ACR,1968 Charger R/T.
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Re: Mopar perf. .620 solid cam spring rates
[Re: bigD]
#2750137
03/08/20 01:32 PM
03/08/20 01:32 PM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,496
So. Burlington, Vt.
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Assuming 1.5 rockers, I’d shoot for 145-160 on the seat, 375-400 open...... for operation up to around 7200rpm. For 1.6 rockers and/or more rpm, I’d be more like 400-425 open. http://www.moparts.org/Tech/Archive/bb/3.html
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Mopar perf. .620 solid cam spring rates
[Re: bigD]
#2750178
03/08/20 03:48 PM
03/08/20 03:48 PM
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Joined: Jan 2012
Posts: 2,645 Stuttgart, Arkansas
rickseeman
master
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master
Joined: Jan 2012
Posts: 2,645
Stuttgart, Arkansas
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Haven’t been here in along time,does anyone know the required spring rates for MP p4349268 .620 mechanical cam. They say to use the p4876064 springs but don’t show any spring rates,just max. Lift. Thanks The book says the 064 springs are 1.600" diameter to be installed at 1.86"-1.88" and have 146 seat pressure and 419 open pressure at a max lift of .640" and are made out of .216" wire.
2011 Drag Pak Challenger
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