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Discussion Starter #1
Background- this isn't in a Dakota or a Durango or a truck. That's getting out of the way first. Next, it's not a Magnum block. The "hard" parts of that conversion are done. The top end is Magnum.

What I've got- everything in front of the distributor for the stock fuel injection including a 5.2 auto OBD-II PCM.

What I'd really like to know is what sensors are critical to not be in limp mode if that's a possibility. This has a mechanical speedometer and currently a carb. I've got a 998 auto. It's got tall gears, so I don't want a speed limit.

It's emissions exempt federally.

So the big high points- it's got stock Magnum heads, an M1 4bbl, stock exhaust manifolds, and a .474 Comp cam. I'd rather convert a Holley 4 barrel intake my throttle body, but I have the stock one too.

I'm curious whose had good luck running what setup on a 408 with an m1 and a significant cam. Would an MP PCM work well? SCT tuning a stock PCM get where I'd like it go?

Any good tuning options to run 87 in it?
 

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87- whats your compression?
start with the SCT- it should get you where you want to go
specs on the comp cam please= hyd roller??
what pistons?
what do you mean by tall gears
998- good trans, which pump? converter?
transgo kit?
 

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Discussion Starter #3 (Edited)
87- whats your compression?
start with the SCT- it should get you where you want to go
About 9.2:1.

specs on the comp cam please= hyd roller??
Flat tappet, XE274H.

what pistons?
Keith Black.

what do you mean by tall gears
2.45 rears right now.

998- good trans, which pump? converter?
transgo kit?
Currently the trans is stock. Last motor it was behind was the mild 360 the 408's based off. Non-lockup. Still straightening things out so if the trans needs anything to continuously live up to 400hp that can be addressed as time goes on.

It's mostly a street car. Should see little time on the strip, maybe a couple times a year.
 

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Personally I'd recommend ditching the OEM wiring harness and PCM and going with an aftermarket stand alone system like Fast or Accel. Bruce bridges has a pretty trick set up he uses for his 6-pack F/I conversion kits he makes for classic cars. It has a "start up" tune pre-installed and it automatically adjusts the tune based on inputs from the different sensors. You can get a custom tune done for it, but supposedly it does a pretty good job with the automatic correcting on the tune.
 

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when you said tall you really meant tall
I could not find a cam card on the 20-224-4 cam but did find that it is a chevy grind on a chrysler core
[email protected]
Comp recommends 254 gears with the 214 cam so I suspect 391's with the 224 cam
so first recommendation
Chrysler .904 Cams are available [email protected], [email protected] .305 lobe lift = 460 lift with your heads
20 degrees shorter on the seat would make all the difference in the world
a under 3 rear end is like taking off in second gear compared to a 354-390
On your tranny
with a tall gear it is hard to get a converter, even a stock stall, to hook up around town = heat
I'd recommend you install a late pump and lock up converter, even a stock lock up, and a big cooler
That big torque motor will give more slip than a stocker
If you decide to later go lower gears later you could use the lock up converter with your new OD trans
ATF +4 with the lock up converter
Cheers
 

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Discussion Starter #6
Lift at the valves IIRC is .512/.517. Here's a link to it:
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=628&sb=2

They're stock Magnum heads with stock rockers. I have no idea what I'd have to do to step up more on the cam further toward the .600 range.

I'm actually not a fan of lockups on anything. Might later go to an OD and lower gears, but currently am sticking with them as it's an ongoing project with a stock suspension. Actually idles like a puppy dog but hasn't been down the highway long yet, I'm currently running a small carb on it. Converter's just 2000 stall.
 

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hanks search did not work on the grind or part number
you did say 245 gears?
If that cam works I'd say it's because the lobe centers are squeezed to 106
just change one thing at a time
you could try 1.7 rockers on the intakes and see what difference it makes
headers?
what weight vehicle
Is this a t-bucket or something light?
I'm thinking it sets up like a powerglyde with overdrive
no bog or flat spot on start up- you got lucky
do you know your head flows? Does more lift help with your heads?
are your heads set up for more lift?
btw that cam I mentioned is around .500 with 1.6 rockers
Is that 2000 stall with a stock converter- you must be really making some torque around 2000
congrats
 

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Discussion Starter #8 (Edited)
It's in an old Dodge F car weighing somewhere around 3500-3600 lbs. It's got an RV-2 compressor on the front of the intake and a pretty full interior. Car pretty much stays in that weight range. It's basically got all the provisioning for the stock Mag sensors done. Just need to grab the ones for the intake and some O2s and I can try out the computer. Ported the stock TB a bit to use.

Had some longtubes on it, but they were a PITA to change the 5/7 plug on the Mag heads so I'm back to log manifolds now. Dual exhaust, but parts are a mess and some restrictive so some of that will likely change too.

Never flowed the heads. They've got some light port work but stock valve sizes and 62cc chambers. Lift was measured at the valves to check for springs. That's about what the number was. Not sure what I'd have to do to the heads to clearance for .544/549 of 1.7s.

The converter's not stock, it's an aftermarket 2000 stall. No bogs or flat spots. Spins up a lot harder than the 360 used to actually. Currently 26.5" tires- but likely will go bigger all around.

I don't want the speed limit because I expect to reach it off public roadways. Can't see that being an issue, but am new to this computer-control.
 

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Higher stall is one way you made this combo work
The other is the slower action of the chevy grind hyd cam
but don't change it yet
try 1.7 first on the intake, then on the ex then both
I'd still say you are on the edge of too much duration for that tall gear but with the looser converter the motor never sees the gear
lots of ways to skin a cat
you found one
do monitor your trans temps this summer
I put a lock up when I switched from a 904 to a 998 in my 77 Pacer Wagon
works great
4.0 jeep block with 258 crank for around 284 inches- 331 gears
I have a couple of OD trans: one Asian Warner Jeep (came with the motor) and one TFOD- have to decide and build one of them- no time
I have run an OD with 3.31s before- would end up about where you are when in OD
Pacer handles like a slot car
 

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Personally I'd recommend ditching the OEM wiring harness and PCM and going with an aftermarket stand alone system like Fast or Accel. Bruce bridges has a pretty trick set up he uses for his 6-pack F/I conversion kits he makes for classic cars. It has a "start up" tune pre-installed and it automatically adjusts the tune based on inputs from the different sensors. You can get a custom tune done for it, but supposedly it does a pretty good job with the automatic correcting on the tune.
if this is in an Aspen they were never made with anything but a carb and never had a PCM I don't count the possibility of it having had Lean Burn being a "PCM" they were a joke.
 

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Discussion Starter #11
if this is in an Aspen they were never made with anything but a carb and never had a PCM I don't count the possibility of it having had Lean Burn being a "PCM" they were a joke.
Correct, currently it's carbed but since it's only going to be about 450hp max the stock FI should be fine.
 

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I still wouldn't limit yourself with a PCM out of the donor vehicle. You will be chasing check engine light code forever unless you get a PCM from a manual transmission truck then it won't be so bad, but you will still have codes that you will never get rid of. I'd still recommend one of the aftermarket stand alones. Would be less headaches in the long run and better tuning ability.
 
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