Re: ? about converting a Magnum 318 truck to 408
[Re: moparsquid]
#1176711
02/12/12 09:46 AM
02/12/12 09:46 AM
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Joined: Jan 2003
Posts: 541 chatham, Ilinois
fox
super street
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super street
Joined: Jan 2003
Posts: 541
chatham, Ilinois
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Get a SCT tuner. Hughes has them.
I have a 408 in a durango with the tuner and it is great.
Last edited by fox; 02/12/12 09:47 AM.
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Re: ? about converting a Magnum 318 truck to 408
[Re: 82ramIndy493]
#1176712
02/12/12 12:14 PM
02/12/12 12:14 PM
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Joined: Aug 2005
Posts: 6,008 Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 6,008
Salem
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This subject has been brought up before and there were some knowledgeable Dakota guys on the board that offered good advice.
My outlook is if you stay with the stock cam the computer should still function as normal and you will still pick up more torque and hp from upping the displacement.
Mo' Farts
Moderated by "tbagger".
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Re: ? about converting a Magnum 318 truck to 408
[Re: fox]
#1176714
02/12/12 11:01 PM
02/12/12 11:01 PM
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Joined: Feb 2003
Posts: 1,532 crisfield, maryland 21817
82ramIndy493
OP
pro stock
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OP
pro stock
Joined: Feb 2003
Posts: 1,532
crisfield, maryland 21817
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Quote:
Get a SCT tuner. Hughes has them.
I have a 408 in a durango with the tuner and it is great.
What all did you do with your 408 build?
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Re: ? about converting a Magnum 318 truck to 408
[Re: fox]
#1176716
02/13/12 12:06 PM
02/13/12 12:06 PM
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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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IIRC LT. Dan has a 408 in his ram...hopefully he see's this thread...408 in a 4x4, I'd probably look at the biggest hughes regrind, which is 218/228@.050, although mag heads don't need that much of a split in duration. I'd almost see if they could regrind it with the 218@.050 lobe for both sides, especially if you plan on running headers and do a little clean up on the exhaust ports. heads, I'd probably look at Enginequests or RHS, the hughes #1110 spring would be a good choice with that cam.
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: ? about converting a Magnum 318 truck to 408
[Re: patrick]
#1176717
02/14/12 08:03 PM
02/14/12 08:03 PM
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Joined: Jan 2003
Posts: 12,861 Gloucester,VA STOP MOVING HERE
RangerDan440
I Live Here
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I Live Here
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Gloucester,VA STOP MOVING HERE
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yes LT Dan has a 408 in his 96 Ram... Up until recently Ive been very happy with it as it now has a broken lifter that totally wiped out my cam and even after doing the autopsy, I cant find a reason why the lifter seized. Anyway, mine is a 4X2 reg cab short bed so its about the same weight as an extended cab Dakota and I built it back in 2004 (wow has it been 8 years already?) to outrun Lightnings, which were the hot truck at the time and I have no problem doing that. Back then, there werent as many options as there are now and honestly I havent kept up with all the new parts that are available for the 318/360 Magnums now so I can only post about what I built and how it runs. My intent for my truck is a little different than the OPs in that its mainly for street use as I dont need it to tow anything anymore, although I have pulled my boat with it a few times and brought my Trans Am home on a car trailer from Maryland last summer, it never bogged and never ran hot or anything. An RV cam would work well with a 408 if extra power for towing is your intent. I have the 2 BBL SMPI M1 intake-I dont particularly care for it for my application but the dual plane wasnt available at the time when I built the engine-go with the DP FI unit thats out now. If I had more cam and/or a lighter vehicle with more gear, it would work better but in a heavy truck it doesnt make the most of the low end torque in a 408. I was running 64 lb Viper injectors at one point but it was too much. Ford has a 48 lb injector that would be a better street application for a mild engine. At the moment Im actually running the OE 318 12 lb injectors since I was driving it daily to work before I wiped out the cam and wanted better mileage. I put a bigger throttle body on it but honestly I cant remember which one I used. Can I claim old man syndrome at 37? I have a B&G flashed computer tuned for street/strip use. My cam specs are: Comp Cams# 20-744-9 lift=.480/.480 Duration @ .050=206/212 Theres no need to go crazy with a cam and remember since you are planning to keep your EFI to keep the duration short since theres only a short time window that the computer-controlled injectors will fire. The cylinder heads are basically stock 2001 Dakota R/T units with some port and polish work. My crank, rods and pistons all came from Mopar and everything was balanced at the machine shop. The pistons are 9.5 MPs. The broken lifters are 1.6 Rhodes units. I run 3.90 gears and a 2500 rpm converter in a 46RE with a simple shift kit and I have a full, true dual exhaust with 2 cats. The above combo was good for a best of 13.37 AT 103, pretty good for a 4400 lb pickup truck, it gets 16-18 mpg and I got almost 50,000 miles on it before it broke.
68 Valiant 408 69 Charger 318 69 Cougar 351W 70 Torino GT 351C 71 Country Squire 351W 71 Road Runner 440+6 71 Satellite sedan 318 73 Duster 318 73 Challenger 383 77 Grand Prix 455 83 Malibu 9C1 383 84 Delta 88 403 87 Grand National 96 Ram 360 09 Crown Vic 10 Challenger R/T M6 15 Challenger Hellcat M6
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Re: ? about converting a Magnum 318 truck to 408
[Re: RangerDan440]
#1176719
02/15/12 10:24 AM
02/15/12 10:24 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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Quote:
yes LT Dan has a 408 in his 96 Ram...
I was running 64 lb Viper injectors at one point but it was too much. Ford has a 48 lb injector that would be a better street application for a mild engine. At the moment Im actually running the OE 318 12 lb injectors since I was driving it daily to work before I wiped out the cam and wanted better mileage. I put a bigger throttle body on it but honestly I cant remember which one I used. Can I claim old man syndrome at 37?
I have a B&G flashed computer tuned for street/strip use.
My cam specs are: Comp Cams# 20-744-9 lift=.480/.480 Duration @ .050=206/212
Theres no need to go crazy with a cam and remember since you are planning to keep your EFI to keep the duration short since theres only a short time window that the computer-controlled injectors will fire.
The above combo was good for a best of 13.37 AT 103, pretty good for a 4400 lb pickup truck, it gets 16-18 mpg and I got almost 50,000 miles on it before it broke.
dang, that's moving for such a small cam. didn't realize yours was that small. it's actually smaller than the roller I put in my 5th ave's 318 (custom Bullet Cams grind, 259 adv, 208@.050, 127@.2, .316 lobe lift/.506 valve lift with 1.6 rockers for both intake and exhaust, 112LSA, 108 ICL) and that idled near stock (17" vacuum at 800 RPM) in my little engine.
with a cam that mild, why were you running rhodes lifters vs. OEM's?
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: ? about converting a Magnum 318 truck to 408
[Re: RangerDan440]
#1176721
02/15/12 07:04 PM
02/15/12 07:04 PM
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Joined: Feb 2007
Posts: 1,025 Las Vegas, NV
dodgeboy11
super stock
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super stock
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
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Quote:
Magnum cylinder heads flow a lot of air compared to any OE LA head so they leave a lot of room for a big cam. But in my case, I want to add a supercharger at some point in the future so I left it mild with a low CR.
Quote:
with a cam that mild, why were you running rhodes lifters vs. OEM's?
I probably should have
It didn't develop some lash did it? Roller lifters don't like lash without the slow ramps a solid cam utilizes to take it up.
All this talk has me wondering if the comp I have will work in a computer controlled application: 216/224 @ .050" 114 lsa. Might be a bit large for a 360 but I wonder if it'd work in a 408...
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Re: ? about converting a Magnum 318 truck to 408
[Re: dodgeboy11]
#1176722
02/15/12 08:47 PM
02/15/12 08:47 PM
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Joined: Jan 2003
Posts: 12,861 Gloucester,VA STOP MOVING HERE
RangerDan440
I Live Here
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I Live Here
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Gloucester,VA STOP MOVING HERE
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Quote:
Quote:
Magnum cylinder heads flow a lot of air compared to any OE LA head so they leave a lot of room for a big cam. But in my case, I want to add a supercharger at some point in the future so I left it mild with a low CR.
Quote:
with a cam that mild, why were you running rhodes lifters vs. OEM's?
I probably should have
It didn't develop some lash did it? Roller lifters don't like lash without the slow ramps a solid cam utilizes to take it up.
All this talk has me wondering if the comp I have will work in a computer controlled application: 216/224 @ .050" 114 lsa. Might be a bit large for a 360 but I wonder if it'd work in a 408...
nope, valve lash was still within tolerance at teardown, thats why I think it was a simple lifter failure. I was on the interstate at cruising speed, ~2500 rpm, and started hearing horrendous noises from the valvetrain-at least I was able to limp it home.
Dodgeboy, you'll be OK with that cam with Magnum heads
68 Valiant 408 69 Charger 318 69 Cougar 351W 70 Torino GT 351C 71 Country Squire 351W 71 Road Runner 440+6 71 Satellite sedan 318 73 Duster 318 73 Challenger 383 77 Grand Prix 455 83 Malibu 9C1 383 84 Delta 88 403 87 Grand National 96 Ram 360 09 Crown Vic 10 Challenger R/T M6 15 Challenger Hellcat M6
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Re: ? about converting a Magnum 318 truck to 408
[Re: dodgeboy11]
#1176724
02/16/12 02:44 AM
02/16/12 02:44 AM
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Joined: Jan 2003
Posts: 12,861 Gloucester,VA STOP MOVING HERE
RangerDan440
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 12,861
Gloucester,VA STOP MOVING HERE
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if anything, your OBD II may throw a code for multiple cylinder misfires because of the bigger cam and longer duration; occasionally mine will do that if it idles for too long. Just reset the code and go.
68 Valiant 408 69 Charger 318 69 Cougar 351W 70 Torino GT 351C 71 Country Squire 351W 71 Road Runner 440+6 71 Satellite sedan 318 73 Duster 318 73 Challenger 383 77 Grand Prix 455 83 Malibu 9C1 383 84 Delta 88 403 87 Grand National 96 Ram 360 09 Crown Vic 10 Challenger R/T M6 15 Challenger Hellcat M6
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