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post #1 of (permalink) Old 01-19-2004, 11:10 PM
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engine swap

hey im just wondering what i have to change from a 4.3 to 5.0L i have a fullsize gmc truck will the 4.3 flywheel work? computer behind the glove box?
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post #2 of (permalink) Old 01-20-2004, 12:34 AM
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Re: engine swap

My guess is neither the flywheel or comptuer will work, but really not sure.
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post #3 of (permalink) Old 01-23-2004, 09:52 AM
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Re: engine swap


I am thinking if they are both MFI/TBI in the same "years". It might be possible, except for the chip possibly due to the advance curves. I would do a check on the sensors. Not to mention going from a 4.3 six to a 5.0 eight. Exhaust might need an upgrade. Whats the story on the tranny?
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post #4 of (permalink) Old 01-24-2004, 02:03 AM
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Re: engine swap

if it were me I wouldn't take a 5.0 (305) over a 4.3. V-8 economy and v-6 power!! If your gonna do shell out a couple more $$$ and get a 5.7.but hey that only my opinion and to each their own.
First, don't use the 4.3 flexplate (flywheel). I think it will bolt up (but not sure) but it will not have the right balance and will cause harmonic vibrations that will shorten the life of your engine (maybe dramatically) Flexplates are cheapand engines aren't. Next, the comp and wiring harness (expept for the knock sensor wire which will probably need to be lengthened) will work fine as will the throttle body and sensors except the knock sensor which SHOULD be changed to a 5.7 sensor and you will PROBABLY need a ecm chip (behind glovebox in a silver box (ecm) under a plate with two screws. You MAY however get away with using the stock chip if the computer is able to "learn" about the engine and adjust enough to run right. (only driving for a tank or two of gas will tell for sure) best bet is to get your new engine AND chip (from an ecm with the same model number (ie 1227747)) from the same vehicle. Oh yeah, I'm pretty sure motor mounts will be in a different place although you could probably use the same adapters used in a v-8 conversion in an s-10 if you don't want to make your own.

All I can think of right now.
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