Without reaserching I bought a painless wiring kit to install a 90 camero tbi onto my 350 in my buggy. after reading the painless directions it states it can only be used with the 1227747 ecm and I have the 1228746 ecm. Are they interchangable? Can I just go through each wire on the schematics to see how they differ? or am I screwed? I have the stock wiring harness from the camero,but thought it would be a pain to figure out wiring colors on a well used set up. Any help is appriciated.

if the box is a Speed Density TBI you should be able to move the wiring around since they use the same sensors...

I think they are a direct swap but you better check each pin, unless something is wrong with the stock harness nothing wrong with using it.

I "forced" a painless harness to work with an 88 camaro TBI. The only thing you will need to splice in is the MAT(air temp sensor in the bottom of the air cleaner) into the wiring harness.

BTW, you do know that the Camaro TBI's were all 5.0L(305 or is it 307, I don't recall) engines right?

From what I understand of TBI computers, they have about a 10% tollerance as far as displacements go.

Lil john,
yes I realized that the cameros have the 305s' and I planned to put it on a 350. I thought (and I am obviously TBI ignorant) that putting the 305 system on the 350 would be like taking off my 4 barrel gas hog and putting on a 2 barrel. It would still run good, maybee not a 40" tire burner but still run good enough and get me some fuel efficiency?

Fuel eficiency no.


but as far as performance goes, its a crap shoot with 305's some run ok, and others run as good if not better than 350's.

I don't believe the 5.0L fuel injectors will keep up with the 350 unless it is VERY mild. I think what you will find is it will run pretty lean.

It really isn't the end of the world since you can easily get a 7747 computer for $30 or less and you can get the 5.7L injectors VERY easy :)

FWIW, I wasn't overly impressed with the painless harness and eventually yanked it and dropped in a stock harness :p But this was in an FJ40 where I ended up with about 3 feet+ of extra wiring and wrapped in a coil about 3 times :eek:

Well i assume he means stock 350, if it's built the chip will need modded because SD systems don't behave well to mods. Can always change the injector constant in the existing ecm if you know how to do that.

Lil john: it sounds like i could make it work with my existing parts, BUT its probly not be worth it if I want to get decent performance out of this 350. So if I understand this correctly my best bet is to find a 7747 computer to plug into the painless wiring kit i should not have bought. Then replace my current "305" injectors in the TBI with some designed for a 350? any good sources for said parts, new\used?

odgreen: are you saying I could make work what I have by "reprograming" my computer? I obviously don't know crap about these systems but I can follow directions to do what it takes to make the changes (as long as there are no special programing tools required).

Open to suggestions

It would require a eeprom burner, you'd either have to unsolder the eprom chip in the memcal and replace it with a eeprom or remove the sticker and use a eprom eraser. It may be more than your willing to do but thought i'd throw it out there in case you wanted to learn how. If your looking for something easier then yes i'd just get a 747 and 350 injectors from the junk yard. Considering most eprom burners cost $50-$100 and most ecm's cost about $25 and TBI injectors should be very cheap it would be up to you if you wanted to play with or or just make it run.

With everyone doing swaps/changes i should offer my services for reprogramming ecms :D

thanks for all the help I'm gonna take the easy way out and just buy the replacement parts. would anyone happen to have the 350 injector part#s for referance?

You should be able to get all the parts at fairly reasonable prices off ebay.

The ECM's go regularly for $30-40. And you should be able to get one that is 5.7L ready :)

I see the injectors on ebay but never really shopped for them so I can't quote you a price range there. But given that a lot of people are "getting rid of them" for larger injectors, I don't think they'd be more than $50-$60 a pair.