5.9 Magnum crate motor
#1982278
01/02/16 10:05 PM
01/02/16 10:05 PM
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Joined: Nov 2003
Posts: 12,494 Western Colorado High Desert
moparmarks
OP
I Live Here
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OP
I Live Here
Joined: Nov 2003
Posts: 12,494
Western Colorado High Desert
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I have a 5.9 crate motor that I picked up for my Dart. It was in a customer's 71 340 Cuda and a found a 71 340 and swapped out the motors. He didn't want the 5.9 and I got it for 1000.00. I bet it doesn't have 200-300 miles on it and thought it was a real good deal beings it included the flywheel, oil pan and intake. I did drive the car with the 5.9 and it ran real good. I'm thinking it is the 300hp version. Ran like 300hp and has the dual plane intake. I would like to get it up close to 400hp. The book says it has a .385/.401 life cam. The 380hp version has a .501/.513 cam but having a hard time finding that MP cam. I going with a 4-spd and 3.55 gears. Will be a street car and will drive on cross country trips. May use 3.23 gears on the trips. Going to run a Holley for now but would like to go to EFI someday. I have a few questions.
What would be a good roller cam? Would like to keep the lifters and valve springs which are the same as the 380hp version.
What is the compression ratio?
What is the rocker ratio?
What is the problem with using a/c on this motor?
What other tricks could I do while it is on the stand?
Many Thanks
72 Satellite Sebring Plus 440, 72 Dart 5.9 4-spd, 68 Valiant, 73 W200, 78 D100 sb, 78 D200, 98 DAKOTA, . Moparmarks Parts & Restorations Desert Mopar Metal Grand Jct. CO 970-261-7039 http://moparmark.com/motormangj@gmail.com
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Re: 5.9 Magnum crate motor
[Re: moparmarks]
#1982300
01/02/16 10:30 PM
01/02/16 10:30 PM
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Joined: Sep 2007
Posts: 14,889 up yours
Supercuda
About to go away
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About to go away
Joined: Sep 2007
Posts: 14,889
up yours
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Pretty much the 380 hp version was a cam and intake change.
Hughes engines has a good selection of cams and a regrind is cheap, assuming you have a good core to return.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
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Re: 5.9 Magnum crate motor
[Re: moparmarks]
#1982324
01/02/16 10:51 PM
01/02/16 10:51 PM
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Joined: Jan 2003
Posts: 390 Wichita Kansas
6PacCuda
enthusiast
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enthusiast
Joined: Jan 2003
Posts: 390
Wichita Kansas
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When I ordered my Hughes roller cam for my magnum engine he asked if it was an efi engine. Told him it was for a carb app and I might put a FAST efi on it later and he found a cam that worked for me. I think it has to do if it is computer controlled like for the Rams and Dakotas.
Last edited by 6PacCuda; 01/02/16 10:52 PM.
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Re: 5.9 Magnum crate motor
[Re: moparmarks]
#1982395
01/02/16 11:49 PM
01/02/16 11:49 PM
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Joined: Jan 2004
Posts: 8,270 fredericksburg,va
cudaman1969
master
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master
Joined: Jan 2004
Posts: 8,270
fredericksburg,va
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Thanks. I was looking at Hughes and they say not for EFI. Wonder why? The cams are different for efi and carb. Carb cam is longer for the mechanical fuel pump, efi cam has no provision for the cam eccentric. 300&380 will work with fi or carb. Went through this myself, ended up buying the RT and 501 cams off e-bay. I wanted the mech fuel pump. Had to change timing cover too.
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Re: 5.9 Magnum crate motor
[Re: moparmarks]
#1982439
01/03/16 12:25 AM
01/03/16 12:25 AM
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Joined: Jan 2003
Posts: 1,482 Lake Orion, MI
goldduster318
pro stock
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pro stock
Joined: Jan 2003
Posts: 1,482
Lake Orion, MI
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Rocker ratio is 1.6.
You'll want to keep the lift under 0.525", so long as you have the R/T springs (these are the straight ones, not the beehive type on a stock 360).
Lunati can make you really any cam you want. I would get something under 230 degree duration at .050 for a street car.
My 340 has a 227/231 .530/.530 hydraulic roller on a 110 LSA with edelbrock heads and 9.7:1 CR and it works well with the 4-speed and 3.23's. Engine made 470hp at 6000 rpm with a 750 dp. It now has SMPI (MS3/Edelbrock Super Victor EFI, which works excellent).
'70 Duster 470hp 340/T56 Magnum/8 3/4 3.23 Sure-Grip
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