I have a 1989 Dakota 4x4 with a 3.9 V6 and AT. I recently have been seeing signs of water in my oil as well as coolant in the exhaust. Fortunately, my AT was recently rebuilt (<500mi ago). My question is can I replace the 3.9 with a 318 V8 and will it bolt directly to the A600 AT?

 

Actually I think I misquoted my transmission, I should have said A500 instead of A600. AT any rate it is a 4 speed automatic that was original to the 3.9 V6

 

yup it will directly bolt up, but if you beat on that 318 much it may not last..... though they did use that trans behind some 318s in newer trucks.... some will try to convince you that you will blow that trans as soon as you fire it up for the 1st time with a V8 in front of it, that isn't true/. If you drive it "normal" and not like a madman that trans can last a long time behind a v8.... WHERE ARE YOU LOCATED?
Have you checked into what's actually wrong with the current engine? It might not be as bad as you think....... how many miles? how good has maintenance been on it to this point?

 

The biggest problem will actually a) finding a LA that bolts right up; b) converting a Magnum to fit or converting the truck to match the Magnum, or c) the depth of the engine bay.

As volaredon says, if you don't beat the crap out of it, the 42RH / A500 will do just fine.

RwP

 

The A500 can also be made into a capable v8 transmission. I swapped in a 400 HP 360 magnum and bolted it up to my A500. However I rebuilt the A500 with quality clutches and steels, servos, shift kit, and v8 hard parts. The A500 is the older 904 with an overdrive bolted onto it. The drag race guys have used 904 transmissions for years because of a lighter rotating mass and more favorable gearing.

The engine swap itself isn't too difficult but pay attention to what Ralph said...each version of the 318 will pose issues that have to be overcome...mostly with engine mounts, firewall to radiator space and wiring. Read through my build thread for a lot of info as I went through different iterations and the problems/solutions of each.

 

Thank you to volaredon, RalphP and robertmee for you responses. To answer volaredon first, I am in Georgia and no I haven't fully investigated what is exactly wrong with my engine other than the water in the oil but it is the original engine and has 180,000 miles. I have to use 20w50 or at least 15w40 oil in it to keep the oil pressure up, otherwise when idling the oil pressure will drop so low the engine light will come on. Yesterday I removed the driver's side exhaust manifold and coolant poured out one of the stud holes so I think she's pretty bad off. The other reason why I would like to install a new engine at this point is that I have just finished a complete refurbishing of the body removing all dents and repainting it, putting in new interior carpet, door panels, etc. so it looks like it came off the showroom floor. The current engine is the 3.9 Magnum V6 so in response to RalphP comments about the Magnum conversion, does that make a difference as far as the engine fitting into the engine bay?


I'm not a speed demon so with my driving habits I think a V8 will not be detrimental to my transmission and it isn't a daily driver. I just wanted to fix it up and pull it out and drive every now and then to show off to my friends....

 

Well, on the LA motor, the exhaust studs DO go into the water jacket ...

Here's a discussion on it: https://www.classicwinnebagos.com/fo...?topic=12531.0

And ... err, no, not a Magnum in a 1989; that was the LA 3.9 . Throttle body injection and a whopping 125HP on a good day ...

If, however, it's already been swapped, then you've done most of the hard work; check out robertmee's and rugged89's threads. Again, the biggest problem will be the radiator fitment at that point. Oh, and add two injector wires and swap to a matching V8 ECU.

RwP

 

I know this is off subject, but where did you get door panels from? Thanks!

 

Don't know where Tech man found his, but these guys seem to have a reasonable price on replacement panels. They're ABS vs the original polypropylene.
https://www.pickupspecialties.com/Do...oor_panels.htm

 

Thank You ragged89!