Needing advice about putting an 88 roller motor in an 81

[JACook]

The '81 distributor probably won't give you the same performance as an '85
would, but it'll work OK. If it's got the dual-sided vacuum advance I'd at least
swap that out for the single style.

[TimS532]

I went by the shop to see how things are coming along with the engine being pulled from the 88 Vert and much to my surprise, the engine, tranny, exhaust, driveshaft, K-member, and full front suspension are all out of the car in one piece (with no cut wires ) We are now ready to put it in the 81 all we have to do is get it to the shop! It's great to have a buddy who has all the right tools and knows the proper way to pull an engine, unlike a lot of "butchers" that are out there. He unplugged everything without breaking one single connector and unbolted everything without using a cutting torch or hack-saw.
We were hoping to get the dash replaced and a new heater core installed before the engine was dropped in, but at this rate it looks like that will be a good winter project for us. I really don't want to hold up progress on the swap, and besides we haven't got the new dash and core yet. I thought we would have more time but apparently not! That is a minor issue we are happy to accept.
I will try to get some pics posted soon of how it looks in stages of the swap.
Again, we want to thank everyone for all the tips and advice. I'm sure there will be more questions arising as the "heart transplant" progresses.

[86 50CPRI]

in reality,there are 12 bolts holding the whole mess in there: 2 struts,8 k member and 2 trans crossmember.Other than that,a bunch of wires cables and hoses.(not including exhaust and hangers) If you are swapping K-Members,its the easiest way to do it.

[plstktnkr2]

OMG, your going to put a newer motor in it? SHAME..youll ruin the "originalit" of the car. you would be better finding an 81 model boa anchor to put in there.

Gee I'm swapping my NA 3.8 stroker out for a supercoupe motor with a stroked bottom end, how does that grab ya???

all I needed was to extend the ECU harness 3 feet to mount it over my radio since the hole in stock locale was too small

[TimS532]

Here are some pics of both the 81 Cobra and the 88 LX donor. Just click on the thumbnail for larger pic.

[Syco Stang]

I didn't read all the responses so I apologize if this has already been posted. I know an '86 Mustang/Capri engine+computer harness plugs right into any '83-86 chassis+dash harness. Connect your tfi, sensors, injectors, plug the right wires onto the starter solenoid and it will work. I have worked on the 79-82 cars on several occasions, and IIRC the harnesses were very similar, could plug right in too. At worst it would require minimal splicing.
You will also need the gas tank, with the '81 fuel level sending unit installed, and the complete fuel lines from front to back. I usually cut them in the middle, under the pass seat, then flare the lines and install fittings for ease of installation. The EEC-IV computer should fit right into the passenger kickpanel, and the harness should route through the correct spots in the firewall. If you were smart enough to remove the harness from the donor car with all the mounting clips intact, it will make for a neater installation if you can actually clip the harnesses to the engine bay. At this point, while the harness is out, I usually use hockey tape to clean up the wire loom and also secure the clips better.
It can be done, is very easy to do when you have a complete donor car, and offers infinitely better driving and fuel economy than a comparable carb setup. Keep it simple, and the car will reward you for it.
SS

[Syco Stang]

I just noticed the pics! That Cobra looks sweet! It's a shame you had to part a convertible. Make sure you get a proper dual exhaust system with some nice polished LX tail pipes!!!!

[kj_80Cobra]

Saaweeet, another Blue on Blue Cobra. That makes 3-4 Medium Blue 80-81 Cobra's owned by members. By the way, mine is getting a '87 302 H.O. speed density setup from a GT donor.

[plstktnkr2]

The hole where the post 84 CPU's are mounted (right kickpanel) is too small to mount an ECU you will need to extend the harness

[TimS532]

Well kj 80Cobra believe it or not Im only 14.

[TimS532]

Ok we tried taking the gear from the 88 and puting it on this distributer and the shaft from the 88 was bigger. My next question is, is there a certain year of Mustang that was a roller motor and a carb? Or will I need to order one?

[79Coupe]

Ok we tried taking the gear from the 88 and puting it on this distributer and the shaft from the 88 was bigger. My next question is, is there a certain year of Mustang that was a roller motor and a carb? Or will I need to order one?

1985

[TimS532]

The '81 chassis is already wired for a perfectly good ignition system. A junkyard
Motorcraft blue grommet module will do everything that DUI can, and you won't
have to look at that hideous HEI monster every time you open your hood...

So let me make sure I'm understanding everything correctly,.....is the "blue grommet module" a distributor from an 85 5.0? If not please elaborate... Does it need to be only for a mustang or is there other models that I can use,...i.e., truck, crown vic, etc...?

I was told by another source (local gearhead buddy) that the distributor from an 85 5.0 mustang will drop right in and will not require a duraspark box, just wire it up and I'm done. Is that correct? If so that sounds like a great option to go with. I don't mind having the duraspark box in the engine bay if it has to be, but if I can clean it up by eliminating it that would be better.

Also, if anyone reading this thread has some good clear pics of how and where everything gets mounted under the hood of the 81 that would be a great help as well. As you can see from the pics I posted, everything had pretty much been removed by PO.

I will try to get more pics posted this weekend of the progress we're making.

[79Coupe]

So let me make sure I'm understanding everything correctly,.....is the "blue grommet module" a distributor from an 85 5.0? If not please elaborate... Does it need to be only for a mustang or is there other models that I can use,...i.e., truck, crown vic, etc...?

I'm not quite understanding this. "blue grommet module" - you mean the duraspark box? I've heard stories that you need to match the wire relief with what was in there. I'm sure the distributor doesn't care, but there's been a lot of discussion about that on these boards before. I don't remember all the ins and outs of it, but a few on here are experts.

I would guess that different models (truck, crown vic - anything with a 302 in it) would work, but the timing curve might be different, so they might not be the "best" option. Again, I don't remember a whole lot, as years ago I made it a practice to buy an MSD box for everything.

I was told by another source (local gearhead buddy) that the distributor from an 85 5.0 mustang will drop right in and will not require a duraspark box, just wire it up and I'm done. Is that correct?

Well, you don't HAVE to have a duraspark box, but if you don't, what were you planning on sending the signal to fire the plugs with? You have to have some sort of ignition box, and the Duraspark box is your cheapest option by far. If the car is already wired for it (and it should be) you should just use that.

If you've got the cash to spring for a capacitive discharge system, I'd do that, but it will be expensive.

[86 50CPRI]

the 'blue grommet box' is essentially the Ignition module that Ford used from the mid 70's to the mid 80's for the Duraspark ignition system. There were other modules during the period,with different color grommets(where the wires go into the aluminum case) to signify different applications.Those also had different wire connectors as well,so they did not interchange.I forget why,or what differences they were,possibly California emissions calibration for one,or heavy or medium duty truck applications for another.I do know there were several.

So...the blue one was most common,I believe, for passenger car duty.They were on everything,all engine packages it seemed:Torinos,Mustangs,F150's, Granadas, Vans,LTDs,Pintos .....you get the idea.

You should be able to find wiring diagrams easily online,and even pics if you try.

[TimS532]

ttt

[JACook]

If you've got the cash to spring for a capacitive discharge system, I'd do that, but it will be expensive.

At this power level, an aftermarket CD ignition box will reward the money spent
with exactly zero added performance or mileage. The factory Duraspark stuff is
more than adequate, as long as it's in good working order.

As long as your ignition system reliably ignites the fuel-air mixture, replacing the
various components with "better" aftermarket parts buys you nothing. Once you
ignite the fuel-air mixture, you can't ignite it "more", no matter how much spark
energy you throw at it.

[Syco Stang]

Nearly every performance oriented engine I've built or installed has yielded some form of improvement with a good aftermarket ignition system, whether it be better gas mileage, smoother idle, or better part throttle acceleration/driveability. I once picked up 50km per tank with just a Crane Hi6 install on an almost completely stock '91 5.0 convertible! However, if you're expecting power gains then you're looking for the wrong thing. Unless your stock ignition system isn't up to the task, you will not see much if any power gains.
SS

[JACook]

Nearly every performance oriented engine I've built or installed has yielded some form of improvement with a good aftermarket ignition system...

What I'm suggesting here is, had you simply installed all new factory parts, you
would have seen the same improvement. Nearly all of these "before vs after" gains
are simply because you installed new parts, not necessarily because there was
any design shortcoming in the original system.

[denshem]

I think I got lost here somewhere. If you are using the injected donor motor and the EEC4 why are you changing dist. gears, or any of the ign.system ,its in the EEC4


And the Dura spark (aka durastone...stone dead) sucks . It sucked when it was new ,it still sucks now that its old . It sucks even more after you add heat, vibration and humidity. Take that early 70'tech and bury it where no one will ever find it

[79Coupe]

At this power level, an aftermarket CD ignition box will reward the money spent with exactly zero added performance or mileage.

I would agree with very little return at this power level, not zero. I always build for now and the future.

"as long as it's in good working order." Yes, and that's what worries me. The part about it working.

As long as your ignition system reliably ignites the fuel-air mixture, replacing the various components with "better" aftermarket parts buys you nothing. Once you ignite the fuel-air mixture, you can't ignite it "more", no matter how much spark energy you throw at it.

Again, I agree that as long as it RELIABLY ignites the mixture, you should keep it. However, when those things die, they don't give you any warning, you are just stranded on the side of the road. Then, after they cool down, it works again. That is frustrating. Just trying to save somebody a walk home.

In addition, I can't tell you how many dyno sheets I've seen where ONLY the ignition box was replaced and cars gained 1/2 - 4 horsepower. If the Duraspark design was that great, they'd still be using it. CD systems are clearly better as they offer the ability to eliminate (or drastically reduce) miss-fires. On the compression stroke, with the Duraspark, you get one shot at lighting the mixture, if for ANY reason, it doesn't fire the plug (and this does happen under normal operation) you just loose. With a CD system, it has the ability to detect a miss-fire and attempt to fire the charge again before the "window of opportunity" closes. Up to 4 times per compression stroke.

My 351W coupe ran with the distributor 90 degrees off with an MSD box. Now, true, it ran like crap and stunk like gas for 10 minutes while I figured it out, but still - it ran. Duraspark would NEVER have been able to pull that off.

However, my hat is off to you, I have never seen anyone so die hard loyal to an ignition system before. And, every post I mention MSD, I can't wait to come back to, as I await your response!

Always a pleasure!

[Syco Stang]

What I'm suggesting here is, had you simply installed all new factory parts, you
would have seen the same improvement. Nearly all of these "before vs after" gains
are simply because you installed new parts, not necessarily because there was
any design shortcoming in the original system.

Unless you're doing a factory stock or concours restoration, I see no need to reuse the factory Duraspark. A well known CD ignition will not only work better, but it also looks better.
Regardless, this particular topic has been beaten to death. Why not get back to the matter at hand and let's stick to what it takes to swap in an EFI roller motor into an early Four Eye???? Arguing about which ignition setup is inferior really accomplishes very little.
SS

[86 50CPRI]

I think I got lost here somewhere. If you are using the injected donor motor and the EEC4 why are you changing dist. gears, or any of the ign.system ,its in the EEC4


And the Dura spark (aka durastone...stone dead) sucks . It sucked when it was new ,it still sucks now that its old . It sucks even more after you add heat, vibration and humidity. Take that early 70'tech and bury it where no one will ever find it

he chose not to go injected,but with a carb and switch over the ignition to ?

[TimS532]

Well I think what we are doing is we found out we can take an 85 GT distributer and put it on this 302 and it will eliminate the Dura Spark box and tons of wires. Im not completely sure because Im new to the engine rebuilding ordeal, my dad has been giving pretty much all the info to you guys cause he knows whats goin on and so much more than me so...

[TimS532]

My son mistakenly gave incorrect information as to what we are going to use for the ignition system.
WE are using a new dizzy for an 85 5.0 with a 5 speed (steel gear)
We are going to see if the original duraspark box will perform well with it, if not the next attempt will be to eliminate the duraspark box and go with a GM HEI control module.
Our budget will not allow us to go with an MSD ignition at this time, but sooner or later, that is where we will get to.
Hopefully we will know something within the next week as to which combo we will use. As soon as we get it running, I will post the results.