Anyone build a Magnum 408 stroker and keep it EFI?
#843990
11/01/10 11:11 PM
11/01/10 11:11 PM
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Joined: Jan 2004
Posts: 2,190
SW MO
closer9
OP
top fuel
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OP
top fuel
Joined: Jan 2004
Posts: 2,190
SW MO
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Thinking about building a 408 stroker Magnum for my '94 (It's a little too much truck for the stock 318), but knowing very little about the ECM and never having built an EFI motor, I'm not sure what my best option is.
Can it be as simple as just bigger injectors? Or am I better off to go with a carb style intake and a stand alone EFI?
Any place I can go to study up on the EFI used, and how it differs from the OBDII that came in '96?
Daily:
'19 Frontier 4WD
Belle:
'67 Belvedere Convertible, 318/727 in Go ManGo!
Other:
'64 C10, 283/3 on the tree
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: closer9]
#843991
11/02/10 12:03 AM
11/02/10 12:03 AM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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LOTTA Dakota guys do it...408 strokers, NOS, AND Boost, and they all kept EFI...some even still pass emissions! PM "lastin" he's got a mid 12 second Dakota running a 408 NA with EFI. (that's a 4200 lbs vehicle by the way!!) 
**Photobucket sucks**
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: closer9]
#843992
11/02/10 12:27 AM
11/02/10 12:27 AM
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Joined: Jan 2010
Posts: 32
Zanesville, Ohio
Last_in
member
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member
Joined: Jan 2010
Posts: 32
Zanesville, Ohio
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Quote:
Thinking about building a 408 stroker Magnum for my '94 (It's a little too much truck for the stock 318), but knowing very little about the ECM and never having built an EFI motor, I'm not sure what my best option is.
Can it be as simple as just bigger injectors? Or am I better off to go with a carb style intake and a stand alone EFI?
Any place I can go to study up on the EFI used, and how it differs from the OBDII that came in '96?
The best case would be to convert it to OBD-II or buy a 96' Dakota because they are still a Gen II yet the first year of OBD-II.
With OBD-II you can tune with SCT, which is a easy if staying N/A. Just email tunes with a tuner(usually hemifever) He got my start up tune and first tune pretty close, but after I bought an Lm-2 I could send him logs. Then he could really nail down my A/F ratios and so on. The truck was basically tuned with out ever seeing a dyno.
SCT has really came down in price too, I think I paid $550 for it two years ago. Now it's like $250 with three tunes.
On my truck, I was running the stock fuel system except for Accel 30# injectors.
If you keep the 94' I would say carb or after market EFI or convert to OBD-II. Maybe find a 96, I just sold a 96' RC SB 318 roller that would of been a perfect donor for you about two months ago.
You'll need a bigger throttle body as well. I have ran the Hughes 55mm throttle body and currently running the F&B 58mm throttle body and haven't had trouble with either one.
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: Last_in]
#843993
11/02/10 09:08 AM
11/02/10 09:08 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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board member Lt. Dan has one in his ram, but I think his is a '96 and OBD2...
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: patrick]
#843994
11/02/10 01:27 PM
11/02/10 01:27 PM
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Joined: Jan 2004
Posts: 2,190
SW MO
closer9
OP
top fuel
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OP
top fuel
Joined: Jan 2004
Posts: 2,190
SW MO
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Well, did a little more digging around today. Hadn't really heard of Ram guys doing this, but apparently it's not that uncommon. A place called B&G Performance will flash my '94 computer for just such a build. Bigger TB, bigger injectors, bigger fuel pump... Gotta do my homework, but maybe bigger cam and roller rockers.
Not something that will happen right away, especially since the truck runs fine now (just needs more oomph), and the Belvedere interior/top needs finished. Will probably just build this in the corner of the garage as time/money permit.
Still interested in hearing about anyone doing this though. Thanks for the replies...
Daily:
'19 Frontier 4WD
Belle:
'67 Belvedere Convertible, 318/727 in Go ManGo!
Other:
'64 C10, 283/3 on the tree
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: closer9]
#843995
11/02/10 07:23 PM
11/02/10 07:23 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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I built my old 94 Dakota with the a 408 and kept the EFI. I converted the truck to OBD2, used the stock in tank pump, but upgraded the injectors to accel 36 lb/hr and upgraded the throttle body to a hughes stage 2 piece.
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: ]
#843996
11/02/10 07:38 PM
11/02/10 07:38 PM
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Joined: Aug 2005
Posts: 6,057
Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 6,057
Salem
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Question for the Members who have done stroker Magnums:
If a stock cam was used, would everything still work on the factory PCM without re-flashing? (OBD 2)
Mo' Farts
Moderated by "tbagger".
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: Grizzly]
#843997
11/02/10 08:35 PM
11/02/10 08:35 PM
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Joined: Jan 2008
Posts: 377
Michigan Troll
blk00rt
enthusiast
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enthusiast
Joined: Jan 2008
Posts: 377
Michigan Troll
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the stock cam is so weak and seems to run out of steam...I would not recommend it.
My stroker ran pretty decent on a mopar performance tune, however it runs really good on the sct tune. If you keep the cl of the cam around 114 it should run alright with a stock tune you might throw a misfire codes every once in a while. You might have to go to bigger injectors too, I had to go to 24 lbs over my stock..I know some people say the stock injectors are 24 but I think they are actually 21 lbs.
Rob Dunn
1976 Dart Sport 360
2000 dakota RT 408 with 150 nitrous
2013 Dodge Ram 1500 Hemi
2009 Jeep Patriot
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: blk00rt]
#843998
11/02/10 09:10 PM
11/02/10 09:10 PM
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Joined: Oct 2007
Posts: 3,953
Oregon
hooziewhatsit
master
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master
Joined: Oct 2007
Posts: 3,953
Oregon
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What are you guys getting for mileage now, and how heavy are your trucks?  (silly question I know, I'm just curious  )
If you ever find yourself in a fair fight, your tactics suck.
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: hooziewhatsit]
#843999
11/02/10 09:23 PM
11/02/10 09:23 PM
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Joined: Jan 2008
Posts: 377
Michigan Troll
blk00rt
enthusiast
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enthusiast
Joined: Jan 2008
Posts: 377
Michigan Troll
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408, 4.56 gears, 4200 lbs truck with a 2400 stall converter ( for now) mileage is about 14-15 highway...maybe a little more.
Rob Dunn
1976 Dart Sport 360
2000 dakota RT 408 with 150 nitrous
2013 Dodge Ram 1500 Hemi
2009 Jeep Patriot
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Re: Anyone build a Magnum 408 stroker and keep it EFI?
[Re: ]
#844002
11/29/10 01:10 PM
11/29/10 01:10 PM
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Joined: Feb 2009
Posts: 900
Illinois
StrkrDart69
super stock
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super stock
Joined: Feb 2009
Posts: 900
Illinois
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Quote:
I built my old 94 Dakota with the a 408 and kept the EFI. I converted the truck to OBD2, used the stock in tank pump, but upgraded the injectors to accel 36 lb/hr and upgraded the throttle body to a hughes stage 2 piece.
Off topic..b5sixpackbee where did you get those valve covers?
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