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Economy Mods for a 360 Ram Van?


jbefumo
12-17-2004, 07:37 AM
Hi All,

I recently picked up a real cherry of an '89 Dodge van
(http://www.befumo.com/new_van.htm), which I fully intend to keep for a while. It's equipped with the 5.9 L TBI engine, 727 Torque Flite
transmission, and (I'm pretty sure) 3.55 gearing (posi). It has 120k miles
on it, and has been very well maintained. Right now it's getting the 13mpg (highway) that was advertised for it when new. I trive it pretty
conservatively, and my main interests are fuel economy and low-mid RPM torque and nice crisp throttle response. My main usage will be for long day trips to cross-country voyages, local runs to the lumber yard, occasionally pulling a 13' utility trailer, and possibly pulling a 2-horse stock trailer from time to time.

My immediate plan is to replace the 727 with an A-518 overdrive unit
(shortening the driveshaft as necessary). First question: It's my
understanding that setting up the 518 to work with a dash-mounted toggle, it will essentially work as a 2-speed rear axle. That is, when in OD, my trans will still shift through the same 3 main gears, but each one will be 31% (or whatever) higher in ratio, as if I had a 2.xx rear. Conversely, when the overdrive is off, I'll basically have the same 3 ratios I have now. Correct?

I'm not sure whether I'm going to go for the one that supports the lock-up torque converter or not. I know there are ways to 'fool' it into working correctly without the guidance of a computer, but I'm thinking I might just hook it up to one of those old-style toe-tap dimmer switches, and have the equivalent of an electronic clutch. (I'd probably hook up a status LED in the dash). Hell, it'll make the vehicle harder to steal.

My second question: I'll probably replace the timing chain sometime in the next year or so, mainly as preventative maintenance, but also to tighten things up. Would it be worth it, being this far into the engine as it is, to install an RV/economy cam and new lifters?

My final question is: What would you do next? I' thinking of the following, in the order I would probably do them:

1. MSD ignition plus a high-output coil & 8.0 or 8.5 mm ignition wires.

2. K&N Filter

3. Headers (with a crossover tube) and dual exhaust.

4. Aftermarket port fuel injection system.

My gut feeling is that I'll probably get the best bang for the buck stopping after #2, and that the next two will probably increase power & performance possibly at the expense of MPG.

Also, I'm reluctant to boost the power too much on a 120k engine, lest
something else break. At some point in the future, I'll consider building
up a replacement for it, pushing the compression up to 9.5 or so . . . but that's a question for another day.

Thanks.

Joe

fredjacksonsan
12-17-2004, 11:41 AM
The older mopars needed timing chains every so often, so that's not a bad idea. We had an old Dodge van with 3speed auto, and 13 is doing good - remember you're driving a big, un-aerodynamic brick with no overdrive.

It may be tough to get mpg and performance at the same time; that's what we all want!! Your idea about aftermarket port injection isn't a bad one, it's likely more efficient than the tbi you have in there now. Headers and K&N will let it breathe, and the ignition won't hurt.

A little better cam would give you the throttle response you're after. On an older engine you're right about not wanting to go TOO big on the cam, as you may be looking at reliability issues. But a little more torque is always nice, especially since you plan to pull a trailer. (and replacing timing chain at same time as cam = make it easy on yourself)

As far as the other transmission, I've heard a little here and there about the 4 speed o/d trannies being unreliable. You've got the 727, which will not break. I'd stick with that for sure.

vandude
12-17-2004, 07:09 PM
Here is a link that will help with your A-518 swap:

http://www.transmissioncenter.net/alto_3.htm

jbefumo
12-20-2004, 07:50 AM
Thanks for all that info & advice. From what I've heard, the A518 is basically a 727 with an extra gear in the tailshaft, but I could be mistaken.

Joe

fredjacksonsan
12-20-2004, 08:22 AM
That's right, now I (think I) remember, it's a bolt-on O.D. unit.

Good luck with the swap!

jbefumo
12-20-2004, 08:31 AM
Now I'm wondering: Could I leave my current transmission in place, and merely bolt on the OD unit? One of the links posted above was to a shop that sells the OD unit for three hundred bucks or so.

Joe


That's right, now I (think I) remember, it's a bolt-on O.D. unit.

Good luck with the swap!

fredjacksonsan
12-20-2004, 08:35 AM
I don't know, they're likely different enough to disallow that. Maybe stroll by your trans shop and ask them, or if you have the new tranny, compare.

'Course it's pretty cool outside about now...

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