i have a 1995 jimmy with the first generation vortec 4.3 and i was wondering what i have to do to make a 4.3 tbi enigine work people have told me the heads are different but i need a second opinion

 

I'm confused, are you saying that you have a '95 with an engine from an earlier year in it? What is it that you are wanting to accomplish?

 

I believe he is trying to go from the CPI motor to the TBI motor.

You are in for a "fun" time trying to make this work... The mechanical stuff will bolt up, but you will have to reduce your fuel pressure to the 8-10 psi required for the TBI system. Where the "fun" comes in is with the engine controls and getting them to agree with the TBI motor. Things are very much different on the control side as the PCM for the CPI motor in 95 was a mix of OBD1 and OBD2 controls. Very specialized for that year only.

What is the problem that you are having to make you contemplate such a change?

 

i have a 95 jimmy with the original vortec motor and i baught a tbi motor and i was wondering if i could use the tbi block and heads and put the vortec intake on it
thanks for your help.

 

In that case, yes, you should be able to use the block. There were differences through the years though so one would have to know the year of the block you are contemplating using. Check out THIS THREAD and associated links to other threads/articles.

Your comment about it being an original "vortec" motor is not entirely accurate. All 4.3L engines have used the vortec cylinder head design since the beginning. It only became a marketing term in 93 when the CPI motor was introduced.

 

thanks