I have a 2006 4.0L V6 with 190,000 miles. I am deciding between rebuilding my v6 with maybe some performance engine parts, or buying a GT 4.6L V8 core for around 500 and rebuilding to factory specification. This is kind of a budget build. I want to add horses while resetting the car's mileage, but still have a platform for performance mods. I will be doing all the labor myself and I dont really care about the "hassle" of swapping the V8. Im purely concerned about which is gonna be better for performance and longevity. No I'm not selling the 6 for an 8. That hassle is way worse in my opinion than the swap/rebuild hassle.

Major things i know i need to replace with the v8 are the transmission, rear end and computer, The v6 transmission is very worn and i plan to replace/rebuild this with whichever engine I go with.
The differential however is more complicated. If i kept the v6, id probably upgrade the diff to an LSD and up the gearing (eventually) which is around the same price as my V8 option; the V8 needs a whole rear end, which is gonna cost me $500 for a 3.31( 900 for the 3.55 is out of my budget), which is the same gear ratio on the six, but with an 8.8 LSD.

some options ive thought of so far:

Start rebuilding the V6, and get an opinion from the shop about the lifespan of the engine and go from there.

Put in the GT rear end, as ill need it for the V8 if i go that route, or ill need it to add HP to the V6 and get an LSD regardless of the engine.

Save my money on the V6 for more engine and other mods.

get the V8 for a bit more money for instant HP and a platform for more mods.

Any thoughts?

I'm not selling the v6 for a v8. Id just get another high mileage POS, that has been for sure driven harder than my V6. I'm trying to make my car more reliable, buying a V8 is out of the question. And look, I'm stuck in quarantine. I don't care about hassle, my options are keep my 6 or swap an 8. This is my project car and I've put in a fair amount of work. I'm not worried about having too much work or whatever. Strictly from an engine perspective, is it worth the extra bucks for the V8 or should I put my money into tuning mods/forced induction for the V6.

 

Sell the V6 car and get a V8 car? Be easier by far to then do the mods... You want a budget build, that's the budgetest you will make for yourself. All the swaps you'll need/mention are already there in the V8 car. All the things you'd upgrade you already have in the car to then go upgrade them.

I'm sure I'm wrong.

 

Way less of a headache and probably more cost efficient in the long run.

 

yes this would be easier but I don't want deal with selling and buying a car, specifically high mileage hard driven V8s. I'm bound to get a POS. I know my V6 has high miles but it's been drive soft and I know that for sure. Im looking to refresh the miles and do some work on my car. I'm buying everything salvage, which helps my budget and may give me some repair work.

Bottom line is I want my car to be unique and a stock V8 is out of the question. Plus I'm in quarantine so I want a big project like this.
strictly from an engine perspective. Is the V8 worth the extra $800 for the engine and computer(yes I know there's more, if I keep the 6 I'm upgrading the diff, trans, clutch, etc anyway) or should I spend that money on tuning for the rebuilt V6. From what I've heard however, there aren't many V6 mods.

 

Ok, well, with all the things you're gonna do/thinkin about doing, the miles ain't gonna matter, nor is the harshness of the driver. If the car's otherwise ok, you should take it and then do the mods. Yes it's a hassle, and buyer beware and all that. But still. You're going to go through the suspension at some point. You're already talking about a non-stock V8. You're already talking about a rebuilt/swapped transmission. And if it's the V8 route you wanna go, then that really means V8 car. Just about *everything* is different between the types. You talk about the hassle of selling/buying a car, well, you ain't seen hassle with a V6-V8 swap. It's not "will it cost more", it's yes, it's going to cost more, and more than you think on top of it all. Both time and labor and parts and...

But hey, you do you. And above all else, the talk goin on in here regarding YOUR car is just that: Talk. At the end, if you do the swapping and things you want to do, and you're happy to have done it, all us saying "MAKE IT PINK WITH GREEN STRIPES" doesn't matter. You gotta be you and do what you want, forget all our opinions.

Now... as to the technical aspects, perhaps you perk your ears up and have a teensy listen... weigh it out... then like Janeway says to Tuvok on *Voyager*, "That makes all the logical sense, Tuvok. We should do that. But we're not, Tom's brash, idiotic idea is more fun. Do it, Tom."

If that's what you wanna do, we can't stop ya and we ain't gonna. Have fun with your car, that's the main deal.

/Also, the stripes should obviously be yellow, duh.
//It never ceased to amaze me that Janeway's old, trusted friend in Tuvok, with the good advice, was ignored repeatedly for the really dumb idea that just happened to work out.
///Which makes me wonder... was Tuvok's advice always wrong, and if so, why was he still on the bridge, or did he have some sort of vendetta against Voyager, or...
////Then I remember what my dad says about Star Trek: "You know, the **** ain't real."

 

What everyone is trying to tell you is that it is much cheaper and less headaches to buy a GT than to transplant a V8 into your V6. There is more to a GT than just the drive train. The suspension systems are different as well. Many of us work on our own cars and understand you wanting a project. I can also understand the history you have with your car and that you do not want another car. It isn't always about the cost. You want your car only what you envision as an improved version of it.

You never really say how you intend to use the car and what type of performance you are after. Do you want the car to be faster in a straight line, corner harder, or brake better? The V8 will accelerate faster, but may compromise braking/handling due to the added weight. I have seen some super charged V6's on a road course that run with the V8 cars due to similar power levels and lighter weight. It is your car decide how you want to use it and build it to perform in that arena. The V8 offers significantly more performance potential than the V6, but it does come at a cost. It you ultimately decide you want to do the V8 conversion, I suggest you start looking for a low mileage donor car that has been wrecked. It is usually cheaper than trying to source all the parts separately. Good luck with whatever you decide.

 

The idea of a wrecked low mileage donor has the added advantage of having all of the parts versus trying to come up with a list.

 

Oooh, that's a good idea. One that's wrecked in the back would only leave an axle and driveshaft to acquire, eh? That might work... Good one, EF!

/I still say do the car swap though...