hi i own a 1987 3/4 ton chevy cheyenne and i need to know can i replace the 5.7 350 thats throttle fuel injected with a older chevy 350 that is carburated the motor thats in it now went bad and i need to know can i bypass the fuel injected carb with a conventional carb so i dont have to use the fuel injected one if so please explain and help me
Yes you can use older motor. But you have to see what your state law let you do. (E-Testing) But there is a few ways you could do this just bolt in the older motor with carb just the basic wiring for the motor starter, alt, one wire for Electirc choke if you have it. any of the sending units for the gauges (you need them off your 87 motor). You can bolt in a older 5.7 motor and put all the throttle fuel injected and sensors & Emission stuff on it. But see what the state law for Emission say about years off motor & E-Testing that they allow. Then once you have an Idea how you going to set it up I sure some one here can give you more detail what you want. Oh that 87 motor and distributor and intake manifold are all computer controled. :The carb would needs older intake manifold for carb set up :you would need a carb set up distributor : So No to the question your asking, on just trying to bolt on a carb will not fit or work.
Is there a reason you don't want to use the injection? The manifold will fit the older engine by opening up/ changing angle of the center bolt down holes on the intake as the holes on the older heads are at the same angle as the rest and the newer heads aren't. This is an easy way to make every thing work as if you don't covert every thing, fuel system, ignition,and exhaust, the computer won't know what to do. Leaving present management system in place is best bet. Hope this helps
you can change it to a carburator. as far as your guages im not sure if the factory ones will still work (if us use the sesors from the 87 motor).if they dont its pretty easy to install an aftermarket guage cluster. as far as the motor if you get an hei distributor it only needs one power wire to work, hook up the alternator the way it was originally, and you will need to change the sending unit in the fuel tank with one from a carburated tank (73 to 86 is all the same, its a direct replacement) hope this helps
If you have a vehicle with EFI, theres no point in replacing it with a carburetor. The only time a person should want to get rid of TBI is when they're upgrading from TBI to a multiport system.