Dcomeau939 New Reader
8/10/21 2:03 p.m.

I'm looking at swapping a vortec 350 out of a 97 Sierra into my 94 c1500 with the 4.3 vortec. Any issues I should be aware of before I start? I would think all I need is the mounts....looking to carburate it. Wondering about the computer, how much of a b**ch it is, etc any tips would be helpful, thanks guys. 

Sgt_Sizzle New Reader
8/10/21 2:19 p.m.

If you have the whole engine harness, ECU and fuse box for the 350 it should be basically plug in. As for carburetting I've seen it as easy as getting a MSD box to run the coils and your done. If you're ever thinking of doing a head swap on the 350 let me know, I have a 305 they would go quite nicely on ;) 


Dcomeau939 New Reader
8/10/21 4:08 p.m.

In reply to Sgt_Sizzle :

Hahaha gotta love those vortecs. By far the best OEM heads in my book, and pretty affordable to maintain. Thanks for your input man!

Cousin_Eddie (Forum Supporter)
Cousin_Eddie (Forum Supporter) Dork
8/10/21 4:13 p.m.

I used to regularly swap GMT400s from V6 to V8 back in the 90s.

Your problem will be the transmission. Both the 94 and the 97 use an "e" transmission. When you go to carburetion, that adds a lot of hassle to control the transmission. If you have a manual trans this isn't an issue of course. They make aftermarket controllers for the auto trans but they're a kludge and expensive too. 

Removing the factory V6 engine mounts pads is a real hassle. Then installing the 350 mounts on the frame is a hassle. Most guys wind up removing the lower control arms to get to the bolts. The V6 engine mounts to pads that cantilever off the back of the crossmember while the V8 mounts bolt directly to the crossmember several inches further forward from where the V6 used to reside.

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