I have a 2wd 94 s10 blazer 4.3 vortec cpi Vin # W and recently i threw a rod out the oil pan ( i think!). I haven't been able to pull the pan off to find out what happened cause i live in the swamp with no solid ground to work on. I'm sure that i'll need a new motor though. The other day i got my hands on a 4.3 tbi vortec motor out of a 94 1500 p/u after i was told that it could be converted. My question is, can i convert a tbi back to a cpi w/o changing the heads,replacing the original wire harness ,or replacing the computer? All i want is the block and oil pan off of this used tbi motor i bought.

 

The heads and the block are different on each engine. I'm pretty sure it wouldn't work.

 

I think just the heads are different. The CPI has screw in rocker studs wgile the TBI engines have nostly press-in studs. Believe the short blocks are the same, You might want to check with a dealer on this.

 

Mission accomplished ! I have successfully converted a 1st gen 4.3L vortec tbi to cpi. I switced intakes, relocated a knock sensor and performed a 94 vin# Z valve adjustment. I just want to thank all the people who gave me very usefull advice and also the people who said it couldn't be done. Oh...and i completed it w/o throwing a single code.

 

As you have found out, everything will bolt together. You won't get the output out of it that you normally should given the head design, but it should work just fine.

Glad you were able to get it together and back operational! Thanks for the feedback. It will help others with similar questions later on.

Also, in case anyone is looking for this again in the future, I'll add the link to a very informative article on the 4.3L and the changes it underwent up to (but not including) the SCFI engine's release:
Rebuilding the Chevy 262 by Doug Anderson