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Mustang v6 Upgrades?

Hello everyone! New member here as of like 5 minutes ago. So long story short i ended up picking up a very nice well maintained 84' with the 3.8 v6 and a certified rebuild on the engine not even 35k ago, And now i know most of you may say "well just rip it out and put in a 5.0" but i'd really like to keep it as original as possible and i was curious if anyone has ever built a 3.8 foxbody? (Maybe like a turbo 3.8?) If so where in the world can i find upgrades?? Because I'm having a hell of a time finding them for a 3.8 v6. Cheers and thank you in advanced! Pics of car will be linked :).


The early v6 (Essex, iirc?) wasn't a good candidate for upgrades. They were plagued with design flaws that show up after squeezing more power out of them. The later v6 (3.8 that came in the 94-04 mustangs and its big brother 4.2 from the f15o) were a different animal. But it would be much easier and cost effective to swap in a 5.0. Just about anything can be done if you throw enough time and money at it, but you have to ask yourself whether it's worth it to you.

Your transmission will bolt right to a 5.0 or later 3.8. You can go carb with a v8, swap in a later ecm and harness to use factory efi, or you can use a number of different aftermarket efi systems. Tons of options. As for the later 3.8, I'm not sure if anyone makes a carb intake. It may exist, but I haven't seen one. That kinda rules out the fitech style aftermarket efi systems. You can rewire it to use the factory efi system from a 94-04 v6, but that's a lot of effort to gain minimal power... unless you're going with turbo or supercharger... which, in that case, again...v8 makes more sense.

Just my $.02. That's about the extent of my knowledge on v6 swaps lol!
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Thanks for the reply! Good to know it can be a tricky engine to deal with. Will probably end up just doing a 5.0 swap after all, sorry to be a "noob" at foxbody questions atm but would an older 5.0 4 barrel be an easier swap for the 84'? ( I only ask since i Found an 85 4barrel 5sp for a good price) And If so are upgrades just as plentful as the H.O EFI versions? Or would it just be more beneficial to look for a EFI 5.0 and do the extra bit of work? Plus is there a cut off year in which the 3speed auto trans won't mount too?
Nothing wrong with the 85 4 barrel motor. Iirc, 85 was an odd year. Maybe roller cam on some and flat tappet on others? Regardless, you'll probably want to know if it's a roller or not before you decide on purchasing it. I would usually opt for a roller motor if given the option. I say "usually" because some of the early blocks (both 302 and 351w) are considered stronger. Of course, they will be flat-tappet... but that's easily remedied by installing link-bar lifters. The downside is that the link-bar lifters are pricey. Expect to pay $350+ and don't even think about buying the cheap ones on ebay/Amazon. They're garbage.
If you're building a mild street car, the roller lifter/spider/dog bone setup is fine. Link-bar style is a little more heavy duty for race application, as the dog-bones can break when over stressed.
The biggest problem with flat tappet motors is that today's oil isn't good for them. You will have to use zinc additives. There is some argument for using certain diesel oils, but it's questionable these days and manufacturers could change the formula and you don't even know it.
Easiest way to tell is by pulling the intake. The lifter valley will have a spider and dog bones to hold the lifters in position. Some early roller motors were "roller ready", but had flat tappet cams. Again, the lifter valley will tell you. You'll see two threaded holes in the middle, which are used to hold down the spider. Non-roller blocks do not have the holes.... only non-threaded oil drain holes. If you want a factory roller motor, don't waste money on a non-roller unless it's a deal you can't pass up (IE: a fresh build with performance parts for cheap). Rollers are easy to find in stock form and cheap.

Another thing to note is that the 85 heads are crap for performance. In fact, most factory 302/351w heads are crap. A popular swap is to grab a 5.0 from an explorer. They should have gt40 or gt40p heads, which have decent flow numbers. (Research spark plug clearance issues with gt40p heads). Earlier e5,e6, and e7 (85, 86, 87-95ish) heads aren't worth the time and money if you are looking to make a little power. If you just want a reliable cruiser, then they're fine. You might even come across some fresh rebuilds for dirt cheap. Some poor saps spent good money having them fixed up before they found out they flow like crap!

Hopefully this helps you and I'm not just rehashing stuff you already know!
Thank you for all the great knowledge and advice! Definitely learning alot of well needed information about a proper 5.0 swap. Good to know some older blocks were tougher, I know a friend with a 5.0 explorer though.. might just have to hagle with him instead haha! Thank you again.