I own a 97 4X4 with a 318 magnum and want to build a 408 to run on the street for added performance and towing. What needs to be done to run a 408 as far as computer programming, cam size,etc? I am old school carb and electronic ign person and am not familiar with computer controlled performance engines. Thanks for any help and suggestions.

i think that you can reprogram the computer yourself by using a chip(BY JET)on the unit.

Get a SCT tuner. Hughes has them.

I have a 408 in a durango with the tuner and it is great.

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.

If I wanted to go with more cam what is your alls recommendation? I also thought about the new style Magnum dual plane MPI intake. How much difference did you see with the 408 upgrade. Mostly low end? Low end and Mid range? Any high end rpm gain? My truck is a full size standard cab 4X4. Is there any need to change stock trans converter? Gearing is 3.54. Not looking to change this if need be but will consider it if necessary. Thanks for input.

I used the smaller cam from Hughes 0814 I think it was. Anything bigger and the computer will have fits. KB quench pistons and a M1 intake. It is still multiport injected. If it wasn't for the guages and trans I'd try a carb on it.

It runs much better than a stock 360 and I can show 19 mpg highway. Actually it run so efficient it is slow to warm up. I've used 3 thermostats and run with the rad. 1/2 blocked a lot of the time. Depending of what gas is in it, it can spark knock. Oh, the CR is at 9.5 Pistons Q-domes were cut of course.

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.

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.

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:

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with a cam that mild, why were you running rhodes lifters vs. OEM's?

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I probably should have

Thanks LTDan, worst case is I'll have to pull the front of the engine apart and stuff a smaller cam in. Since I already have this one I figure it'd be stupid to not at least try it. Going in my dad's 2000 Dakota.

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.