swapping 4.3 vortec for 5.0 or 5.7 vortec

[jeff hosford]

My 96 astro gave up the ghost so thinking about v-8 swap. Has anyone swapped the 4.3 vortec for a 5.0 or 5.7 vortec. Was looking at my brothers 96 chevy truck with a 5.0 vortec looks the same. Wondering if it would be plug and play or is there a difference in the wiring. And cost of the engine is about the same.

[GnarliSafari]

do a search in the engines section, im unsure if the 5.0 has ever been sucessfully swapped, but plenty of 5.7s have as well as even larger blocks.

[Smiliesafari]

That swap has been done so many times that it's almost common. The external dimensions for both the 5.0 and 5.7 are the same. Either will be a great replacement for the 4.3. Depending which fuel injected version you use ie mfi cpi tbi will determine how involved the wiring will be.

[jeff hosford]

What I was thinking was to pull the V-6 vortec out and put a V-8 vortec in. I have looked at a V-8 vortec and it looks to have the same injection as the V-6 vortec. Was hoping to use the same harness as the V-6 and computer. I have looked on the forum and did not see anyone that swapped vortec for vortec unless I missed something.

[v8famvan]

Jeff,
You are correct in thinking that the swap is do-able. The injector connector, however, will have to be changed for the additional 2 injectors, Computer re-flashed/replaced & other minor items.

[jeff hosford]

Thanks for the input sounds like some wiring will have to be modified. what other minor things have be done. just don't want to go into this blind. Will I need part or all or the harness off of the donor vehicle and the computer.

[thevalleyboy]

Jeff check out this area of the forum

viewforum.php?f=8

don't get too hung up on the word vortec, my understanding is basically anything after 1993 or 94 is "vortec" - when talking about these specific displacement engines....

http://en.wikipedia.org/wiki/Vortec

[gabequest]

Check out my post under V8 "Ladies and Gentlemen, Rock and Roll".

The oil pan was a bit to big (7qt) and rested on the front axle housing, but other posts will help you figure that out. Yes keep the computer and have it flashed and reprogrammed because of some security lock and to have tire size/gear ratio match. Again, other posts will help clear details up for you regarding this as well as the radiator, trans cooler, removal of oil cooler, exhaust work etc.

I had a GM tech put everything in once researching and finding parts, because I'm amateur hour and it would have taken me way too long to figure it out...........but lemme tell you, the V8 made me giggle like a little girl for a solid week after it was dialed in! Don't put another 4.3 in it. Succumb to the obsession these vans bring forth!

[jeff hosford]

Gabequest how much did the programing and harness mods cost you and do you have a web address or phone number for Dave at cpe thanks for the info.

[gabequest]

I'll have to check on the pricing for you. From what I gather, rewiring the harness shouldn't be too hard on your own, especially if you are capable of doing the swap yourself. There may be something on this procedure in various threads or archives. I used a company called Howell Inc (810-765-5100). I believe they will do the computer too, but don't know the prices, but Dave was cheaper. He'll be even cheaper now because my application was new to him so he had to spend a little money on his end to get it dialed in. You won't accrue that cost. Dave at CPE (303-794-6701). He's in south Denver so I just dropped mine off to him. Don't know what shipping is. He may even do the wiring too. I'd get quotes from both places. Others on this cite may have other suggestions as well. In terms of the technical nitty gritty, I'm pretty limited. Hope this helps.

[jeff hosford]

Thanks gabequest for the info. Is there anybody on here that has modified their harness themselves. Just want to know how involved it gets might just do it myself.

[Smiliesafari]

A few years back I bought a wiring harness from Howell Engine developments. It was for a 4.3 swap into a Jeep CJ. It was a plug and play harness. The highest quality, although a bit pricy. But then you get what you pay for. Somewhere I heard that Bill Howell was the president of GM's Packard division. That explains the quality. If you have any question about the wiring it would be a good bet those guys can help. When I do the V8 swap I was thinking the wiring and ECU from the 4.3 will work just fine. The connector for the CPI will have to be modified. I plan on using a CPI 305 roller. And the term Vortec is in reference to head design.

[jeff hosford]

Thank for all the info. Still searching the info I can find on this swap so hopefully thier will be no surprises. lol

[lockdoc]

Either get someone to do it for you or get yourself some factory manuals or wiring schematics off the net and figure it out yourself. There are a lot of different options that have been done in terms of what size engine and what kind of fuel delivery systems used in V8 swaps. As said before, Vortec means nothing. What matters is are you going carbed, TBI, SPFI, CPI, OBD1, OBD2, etc. A 96 comes as OBD2 with sequential fuel injection. Very similar to the late model "Vortec" 5.0-5.7. The only swap that is virtually plug and play is the V6 TBI to a V8 TBI setup. All that is involved is lengthing a few wires and replacing the chip in the computer. On yours you would need to add some wires and have the computer reprogrammed. I have done TBI to TBI, CPI to TBI and am now in the process of going OBD1 TBI to OBD1 LT1 using an OBD2 LT1. Each one I have had to study untill I understood then did it.

[jeff hosford]

I was thinking of keeping the stock CSFI injection that the 1996 and newer came with. Thanks for the info when I get a motor I will get wire diagrams for the donor vehicle. So if I under stand this right I must use the computer that came with my astro van and have it reprogrammed.