hello , I have an '86 t-top hatch with a crapped out 3.8 V-6 coupled to an auto tranny.  The engine must have been poorly maintained by its previous owners, becuase when I took the intake off, the coolant passages were blocked up with a carbon/cruddy mess.  

here is the real problem, I have heard that the 3.8 engine was a poorly made engine in 1986, and I was told by my mechanic that I could easily swap in a 3.8 from a later mustang (94-98) only I cannot find a donor car with low miles.

I am trying to keep the repair costs on the low side, as I am heading to college soon. so far, I have found a couple of higher mileage 3.8 motors for around 500 dollars, and I have a friend who is willing to let an 86,000 mile 92 5.0/auto cougar (salvage title) that runs perfectly go for around 300 dollars.

am I better off going the route of swapping in a V-8, the cougar is complete, I just need a few various parts like motor mounts to complete the swap.  or would I be better off finding another V-6.  If there is any literature on how to preform this swap that anyone knows of, that would be a help.  I know my way around a car, only I have never preformed a swap before.

I just would like to know what is more worthwhile, as my ultimate goal for the car is to have a V-8 in it.  I just dont have the real $$$ to get it done professionally

If you get the correct motor mounts, and parts such as the radiator, accessories, wiring harnesses, and computer, it should be a pretty easy swap.  Just remember, you will also need a rear and a driveshaft from a 5.0 too, and I'm NOT exactly sure the rear from the Cougar will fit, if someone else can chime in here and verify that.

I have an 86 myself, but mine was a factory GT, so I never have done the 6-to-8 swap on my car. This is just what I know from friends doing this.

Mr86GT

Hey,

I think it is definetly in your best interest to switch to the 8cyl.  You will have to beef up the front suspension (or it would be a good idea) as the 6 cyl is much lighter.  If you can find the parts needed in a wrecker yard you can save a tonne of bucks too.  You probably won't use much of the cougar as a donor car but engine tranny and possibly rear, but you can always part it out.  Really not hard to do, take motor/tranny out put motor tranny in!!  I know not much help but that's about it!!

Be carefull!!  I think that the V6 cars have a different K member.  I know that 4cyl cars are interchageable, but I think the V6 cars were unique.  I would not invest money into a 3.8.  Trust me there are a lot of hidden costs to a "good" V8 retrofit.  (brakes, suspension((swaybar, knuckles, etc))  I transformed an '84 here is its history;

Started as a 2.3l 4speed.  Swapped in an '80 302 with dart jr heads and a 5spd ( lots of work)  Blew up that engine, sold the heads.

Next was a doner 5.0 from a 90 GT convert.  with some suspension mods and conversion to carb car ran a 13.2 @102 (low buck hotrod)

Now a '65 289 w 11:1 AFR heads big solid cam, C4 auto and 4.56:1 gears should put me at about 12.50's 

Anyway it can be done, but check that k-member

You will also have to change the k-member..as the 6cyl one will not work with a V8  

go v8...I also have an 86 t-top hatch that was 4 banger and now has a 351 cleveland. i am still using the same rearend in it. both the mustang and couger a fox bodies, so the couger SHOULD have everything you need. the k member, motor mounts, tranny, driveshaft, computer & wiring harness, to the rearend  should even work. i am not sure about the springs though