305 Computer running a 350?

[kustomss]

I'm currently trying to throw a '93 TBI 350 in my '85 Monte. I only have a V6 car so I was wondering if I could simply swap the computer to one out of a 305 car. I'm thinking the O2 sensor would see that the tune is too lean for the bigger engine and adjust for it. Does anybody know if this will work? I do have the computer and harness to the 350, but it's way different.

 

[L.A.X-RATED]

I do not know if this would work(sure someone can chirp in) i do have a computer along with complete engine harness for an 87 mcss that im eliminating from my project build.also available are the intake,quadrajet(elec) and dizzy.all of this is in great working cond.if you can use the harness and computer,id let them go for60.00 shipped.pm me if interested.

 

[Clone TIE Pilot]

V6 and V8 computer harnesses are different. You will need a 305 CCC computer harness and ECM. 87 V8 harness is different from 85 V8 harness.

 

[kustomss]

Whats different between the two harnesses? I don't see why they couldn't have used the same harness with a different computer.

 

[Clone TIE Pilot]

Whats different between the two harnesses? I don't see why they couldn't have used the same harness with a different computer.

V6 and V8 harness are laid out differently, which means some of the plugs for a V6 engine may not reach where they should go on a V8 without soldering in splices to make them reach, never use climping on computer wires. V6s and V8s also use different EST modules in the harness. Not sure about this but the ECM sockets may have different pins in them. Pre 87 MCs use a TVS and vacuum valve controlled EECS, post 87s use a computer controlled EECS.

 

[RITTER]

If you have to swap the computer and harness :idea: I wouldn't even consider putting a 305 computer in it Especially since you already have the 350 harness and computer. The ignition is controlled by the computer and the 305 and 350 obviously have completely different camshafts, so therefore the timing will be setup differently.
As far as the harness goes, if the harness that is in the car has all the connectors and is the correct length ... you can use it :idea: The harness itself will have no effect on the performance :wink:

 

[Tank]

I would go ahead and use the 305 Computer harness for the 350 set up. The computer uses a set of programmed algorithms that take the input data from the sensors (which is usually ohms) and then computes the correct output signal needed to make any adjustments to the performance of the engine and transmission.
Assuming your using the same model of transmission as what the computer came out of you should be fine.
Basically, thru the sensors the computer will be able to regulate fuel pressure, spark, emissions monitoring and etc.
As long as the 305 you are taking it off of is the same model year as the 350 your putting it on it should work.

The firing order will be the same on a 305 and a 350 as well as most of your timing set ups.

Camshafts are interchangeable between a 305 and a 350 as well.

The only mechanical difference is the bore of the pistons which gives the additional cubic inches and makes it a 350.
(Note: this does not take into count the difference between the Main Journals on a 2 bolt and 4 bolt main)

So in conclusion as long as you have the same sensor setup on the 350 as the 305 I don't see any problem with swapping them out.