engine swap worth it: stock for stock?

[sinistral]

any real benefit (vs. time/money involved) to swapping out the CFI 5.0 in my '85 colony park for a stock 5.0 in a '91 colony park?
would wiring harness / ECM be a direct fit from the '91 to the '85?

(speaking of wiring harnesses for the engine: when people talk about grabbing 'em for engine swaps, what all is involved in this particular harness? does it go to components like speedo, tranny, "idiot lights", etc., or is it just the ECM talking to the engine? if i'm at a junkyard to snag one, am i crawling underneath following wires back to the fuel tank and having to tear apart the dash? or just unplugging connectors under the hood?)

thanks in advance.

[sinistral]

of course i would freshen up the '91 before dropping it in, just nothing fancy like head porting, etc.

[fmansfield444]

Yeah it'll be worth it, especially if you just have the parts lying around in the 91. 91 may be a little different but I swapped a harness from an 88 in my 85 and it was pretty easy, all one piece and all the connectors were under the hood.

It'll be a lot easier for you since you have an entire donor car to work with.

If you're swapping the whole motor and not just the SEFI stuff it would also be a good time to add Improved intakes and some other HO stuff as a 91 302 would be able to handle all that (injectors and cam).

[tjc78]

If your swapping the motor and converting CFI to SEFI there is really no reason not to go HO. Find a Mark VII HO donor car for the engine, injectors, and computer. There are a few writeups here for CFI to SEFI conversion and what car makes the most sense to snatch a harness from. Some years are integrated cruise control and some aren't, etc.

[sinistral]

I've looked through the CFI conversion threads, and read about the Mark VIIs, Mustangs, Explorers... I'm just wondering about the more simple swap from '91 to '85. I know it wouldn't be as strong as the aforementioned, but, presumably, it is a straight swap (instead of looking for various parts from this and that model, rotating intakes, swapping heads, jerry-rigging TV kickdowns, etc. etc.)

Ideally (in my head) I'd grab a complete motor from the '91 and drop it and the ECM/harness in the '85 and be done (and thus the CFI conversion is complete).

Now, since I'm doing all the same "work" (forgetting for a moment having to also track down other donor cars and parts), would it be worthwhile over the more traditional upgrade (Mustaing, Explorer, Mark VII).

Just looking for opinions (anyone know off hand what the HP/torque rating was for a '91?)

Thanks.

[fmansfield444]

Other than just dropping the 91 motor in there's a few more things to complete the swap, fuel lines need modified, ignition circuit needs spliced in, and the others you have mentioned.

Some other annoying things like the exhaust, NSS, and all that.

But if you already have the 91 then it's still worth it. There's definitely a boost from lopo CFI to lopo SEFI. Also with the 91 motor you can add more things when time/money allows.

But if I was going to put a 91 motor in my car I would add the HO/explorer stuff while its out. It wouldn't take much once the motors already out. Probably an extra $100 at the junkyard for all the stuff you'd need.

91 harness would be fine just ignore the integrated cruise and use your standalone cruise. Also the NSS is easy to get to on the 91 harness whereas I still haven't found the connector for it on my 88 harness. Plus with 91 you can wire in heated O2 sensors.

[sinistral]

"NSS"?

also, what is integrated cruise vs. standalone cruise?

what is advantage of heated O2 sensors?

thanks.

[fmansfield444]

NSS is the Neutral safety switch that will need to be wired into the new computer from your transmission. Without it wired in you will get a high rev startup and won't be able to do a key on engine running test.

About the cruise, I'm not sure the exact year it switched but your 85 will have cruise control separate from the engine computer whereas the 91 will have the cruise control integrated into the engine computer.

And I believe the advantage of heated o2 sensors is it will give the car a better air/fuel mix on cold starts.