Hey guys my son and I are doing a 305 to carbed 350hp 350, I am understanding that i can use my current harness and cut back unused wires. This way my stock tach and dash is unaffected, am I right because I am not sure about all the fuctions of the ecm. Some clarification would be great thanks!!!

 

The car is a 92!

 

was the car originally TBI or TPI? You will need a wiring diagram to figure out which circuits to keep. The tach, coolant temp, and oil pressure are easy. The speedo depends of which you had. TBI cars had a buffer box between the speedo sensor and the gauge cluster. TPI cars had this function inside the ecm. I need to know what harness is on the chassis to give you the right diagram.

 

It is a TBI, what functions does the ecm have and will i still be using it? Thanks for your help we will put some pics up soon.

 

You won't need the ecm to drive anything unless you have a 700r4 or 4l60 4 speed auto trans with a lock up torque converter. You'll need a lockup control kit to make this work. Don't discard that ecm. You never know when you or someone else is gonna need that box.

You will probably have to rewire the starting circuit to remove the VATS (vehicle anti theft system) so it will start with out the ecm. When I get home tonight I'll post up the wiring diagrams for the TBI car.

 

I am keeping the what i believe is the 700 r4 auto 4 speed

 

If its oe then its a 4L60. Its the same as a 700-R4. You'll be able to drive without the lockup torque converter function it'll just make less gas mileage. I dunno how much I never ran mine without it to see the difference.

 

Here's those diagrams i promised.

 

TBI diagrams continued.

 

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What is the difference between the 2 trannys?

 

one is manual and one is the four speed auto.