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Discussion Starter #1
Curious what the Tbird Cougar hive has to offer for my almost 30 yo throttle body injected 4.3L Chevy truck. Does a 350 TBI swap seem not worth it? Not too tough?

I could use some extra power to pull a boat on occasion but I know 4.3L engines are still available and that would be the easiest project for a beginner like me. I need to find the best forums to research this type of work. Stock manual 5-speed in the truck now.


Maybe after this a new motor for my bird would seem like less of a challenge.
 

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4.3 V6 or V8?

If V6, I'd consider hard the 5.7L V8 upgrade. Or a LS upgrade.

Depending on the year, they may be almost plug/n/play in the chassis. Or PNP with minimum rewiring. Or with an aftermarket harness.

RwP
 

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Discussion Starter #4
thanks guys I was thinking about going from stock 4.3L V6 to the TBI 5.7 or 350 V8 stock. This would be simple like pull and replace and rewire. Not as many 5.7 V8's test out for compression these days but I wanted to hear about changeover issues.
 

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Discussion Starter #5
So far, most of the youtube vids I've found show problems and frustration. Different motor mounts and a new wiring harness, not sure on the computer.
 

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Huh, so you have something like an 88 Chevy S10 with the V6 4.3L ??? Yeah .. it wasn't so good then, all the way up to 1995. I ran into a lot of wiring and electrical issues among other things in the dashes on those trucks. When I say that I mean fried harnesses between the fuse box and the ignition switch ..

Those 4.3 didn't really improve until they got the 1996 vortec heads and then the CPI intake. I still don't like TBI or CPI - but you can pull more like 190 HP out of those from 1999 and later. Of course youd need to be re-wired for the computer, and extra smog equipment / tuning optional, etc ..


Still not a lot of power to pull a boat though, maybe a little dinghy or jet-ski no problem. At that rate, better to swap to the V8. Of course the TBI 5.7 is going to give you more bang for the buck and be easier to install. That LS would be a monster, but require more $$ and wiring for the computer, etc ..

Either V8 swap is going to require new radiator, mounts, and you may want to upgrade the rear end or transmission - from what I remember, they were putting Borg warners ( piece oof **** ) in the 4 Cylinders and Tremec (much better ) in the V6 with a better rear axle. If you're automatic .. you're going to need a new transmission sooner. LOL

Plenty of information out there on these kind of swaps, these were very common back in the 1990's to find minitrucks with V8 swaps.
 

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Discussion Starter #7
Actually my truck is full size single cab 4wd. I'm surprised when I read some people don't like TBI. 30 years with no fuel issues put some money in the bank for me.

The youtube stuff I find is mostly old and still at the end of the era of swaps and mods for these old trucks. One problem is I can't find a similar V8 truck that hasn't been used up already to simplify to just a v8 engine replacement.

Thanks for commenting.
 

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Rebuilt small block chevy’s are so cheap, that it’s hard to not justify the v8 swap. I think a good swap, while still keeping it on a budget and making the wiring easy would be a 350 with vortec heads, and gm actually makes an intake manifold that bolts to the vortec heads but has the TBI throttle body flange.
 

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Q: What emissions drama will you have to deal with in WA? In CA, legal engine swaps require all sorts of drama to make sure you add all the emissions equipment the new engine had and some of what the chassis had.

If your smog/emission checking requirements are minimal/none, it seems that mostly turnkey TBI harnesses can be fairly affordable.
https://www.ebay.com/i/221943836783?chn=ps

Q: I'm a little ignorant here but did the 350 TBI ever come in your vehicle's chassis? If so, can you just buy those brackets or pull them from the junkyard?

Q: What accessories might you have to re-plumb in your truck to match the new engine? Example: do you plan to carryover the AC? Will a PS pump be in close enough position to reuse the existing hoses or will you need to customize that?
 

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Considering they still sold leaded gas in WA when I was visiting in 1993, I have a feeling the emissions requirements aren't too tight.

Al
 

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Discussion Starter #11
I'm in Eastern Wa where there are no emissions tests. Going non stock will reduce my resale market, some coastal guys won't want to look but I'm not worried about that.

The vortec heads are making my head spin a little. They get suggested for v6's and v8's. Some mods are required to use them on my v6.

The v8 with vortec, does that mean 8 injectors? or a single throttle body injector? I've been reading a change has to happen to my v6 throttle body to swap to v8.


Yesterday I read all the stuff on v6 upgrades in the link above and they are starting to make sense except for the vortec heads and a new cam will always be a ? The underdrive pulley, better valve springs and electric fan seem easy enough. I'm better prepared to just bolt in a complete engine and bolt on some new parts though.
 

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Discussion Starter #12
Q: What emissions drama will you have to deal with in WA? In CA, legal engine swaps require all sorts of drama to make sure you add all the emissions equipment the new engine had and some of what the chassis had.

Not much of an issue, no inspections.


If your smog/emission checking requirements are minimal/none, it seems that mostly turnkey TBI harnesses can be fairly affordable.
https://www.ebay.com/i/221943836783?chn=ps

thanks for the link, lots to learn and study .


Q: I'm a little ignorant here but did the 350 TBI ever come in your vehicle's chassis? If so, can you just buy those brackets or pull them from the junkyard?

Yes it did come in my chassis. I read the motor mounts are not very removable and custom stuff happens. Have not seen any plug in play parts for this swap yet.


Q: What accessories might you have to re-plumb in your truck to match the new engine? Example: do you plan to carryover the AC? Will a PS pump be in close enough position to reuse the existing hoses or will you need to customize that?
I have aftermarket A/C and stock power steering. I'm not sure what will be needed but this is a minor concern to me compared to engine and electrical stuff.
 

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I don't think an engine swap that is done properly is going to hurt your resale value, if anything it might increase it since you would be going to a more desirable engine. What depreciates a car is a hack-job engine swap, things like wiring laying all over the place, a carburetor on a vehicle that was fuel injected, things like that.

As for the vortec heads, that refers to heads that came on vortec motors. The first thing you should know is that a chevy 4.3 is a chevy 5.7 with 2 cylinders lopped off. They have the exact same architecture, same bell housing pattern, same motor mount locations, same front accessory bracket locations, same water pump, same bore spacing, same bore and stroke, same intake and exhaust ports in the cylinder heads, etc. Vortec heads refers to the heads that were factory installed on the vortec motors, which were available in both V6 (4.3) and V8 (5.0 and 5.7). Installing vortec heads on a 4.3 will require installing the complete vortec intake setup, with sequential port injection, however since the V8 heads are plentiful and cheap and arguably the best factory head ever made for the small block chevy, numerous aftermarket intakes exist to allow you to run vortec heads on a chevy V8 with either a carburetor, or in your case, the TBI injection unit. So my suggestion would be buy a reman'd chevy 5.7 V8 with vortec heads, get the intake manifold to continue to use the TBI, wire the truck like a factory TBI V8 truck would have been (would be best to find a beat V8 donor truck for the wiring, ECM, and V8 TBI unit), and have a factory looking engine that makes double the horsepower, but will still idle and drive just as smooth, and last you another 30 years.
 

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My neighbor has an S-10 with the V8 mod you're describing; he did not have to swap a lot.

His biggest issue has been the EGR stuff; IDK how to mess with Chevys, lol.

EEC harness, underhood harness, and a few wires were all he swapped, IIRC.
 

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V8 is basically the same as V6 .. that TBI intake is just a throttle body with Two fuel injectors inside it. You didn't get 8 or 6 injectors unless you went with the CPI which was a spider manifold of fuel lines, then you would have the corresponding number of injectors in one central location in the manifold itself. You wont get traditional injectors / fuel rail unless you went LT or LS series engines. Fuel injection is the key to engine longevity and economy if that's what you are ultimately going for versus cost and ease of swap.

Shouldn't be hard to swap TBI for TBI as far as wiring goes - but you'll need the correct computer to run it.
 

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Discussion Starter #16 (Edited)
MadMikeyL,

350 with vortec heads and tbi...

That sounds like the swap I should and maybe could do. It may be so easy that no one made a video showing the swap. Some videos I found told the v6 mounts are in the wrong spot for v8 and have blind bolts that require new mounts ones get made. An extra 4 inches to the block length makes sense to me that mounts and location might change. One guy cut holes in his truck to get to the blind motor mount bolts.

I have found aftermarket 350 tbi swap kits are out there if I can't find a donor vehicle.

Edit... I started searching for this combo but the only cheap vortech 350 motor I could find is for carburetors. That might be worth it to get the better heads and have less electrical and programming issues.
 

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Yes, other than an intake manifold swap and a tune, the vortec v8 swap is no more complicated than a regular tbi v8 swap.
 

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I don't see why you would need to cut holes or anything - they did offer your truck with the factory V8 option. Im sure the motor mount brackets are different, but those should be very easy to find along with everything and anything you could ever want to do to that truck.
 

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Discussion Starter #19
A compression test today yielded 150 psi in all cylinders and oil pressure has never changed. So I think I am ok with what I have but it sure is gutless compared to my Tbird.
 
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