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4.3 cpi to a 4.3 tbi motor swap

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Old 11-30-2009, 11:02 AM
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Default 4.3 cpi to a 4.3 tbi motor swap

i am going from a cpi to a tbi motor in my 1994 sonoma ive got a 4.3 tbi truck sitting in my yard and my cpi motor has a bad cyclinder i figgered it would be ceaper to just put the tbi motor in my sonoma but the tbi has two injector wires and the cpi only has one can you change the motor wireing harness thanks
 
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Old 11-30-2009, 11:06 AM
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Why not swap the CPI intake to the TBI engine? Thats what I would do. But yes if you have the correct TBI engine harness and change the fuel pump it will work. Im pretty sure the CPI takes more fuel pressure to run than TBI. Of course they may be the same pump and just have it regulated way down for TBI. I dont know , would have to research it.
My vote is just swap the port injected intake over
 
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Old 11-30-2009, 11:17 AM
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are the heads the same or do you need to change them too thanks
 
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Old 11-30-2009, 11:22 AM
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Shouldnt have to change the heads, just intake manifold
 
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Old 11-30-2009, 11:25 AM
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would it be easyer to change the intake or are the wireing harness interchangeable at the firewall thanks
 
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Old 11-30-2009, 11:38 AM
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Wiring harness should be interchangable at the bulkhead connector at the firewall. The CPI engines make 15 to 20 more HP and are eat up with torque. That alone would sell me on doin the intake swap. TBI injection on a 4.3 is kinda turdy imo
 
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Old 11-30-2009, 12:06 PM
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MUCH easier to just swap the intake, but the cam in the CPI engine is different as well. If the cam was still good in your old CPI engine, you could swap that over as well.

Check out the article below:
Rebuilding the Chevy 262 by Doug Anderson courtesy of EngineBuilderMag.com
 
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Old 11-30-2009, 12:12 PM
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im not really worryed about performance i just want it to run i will change it out again when i have more time to mess with it thanks
 
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Old 11-30-2009, 12:18 PM
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You dont have to change the cam . It will still run with the TBI factory cam
Still easier to change the intake no matter which way you look at it.
 
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Old 11-30-2009, 12:29 PM
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It will definitely run. Just not as well.
 


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