Stroking from 3.8L to 4.2L (1995 V6)

StoicPanaphobic · Dec 8, 2013

I really wanted to start upgrading performance because my Mustang is going to be repainted with new wheels.

However, my engine has 253,000 highway miles. I want to do a rebuild/stroke it out to 4.2L.

The numbers feel very anemic compared to my former Daily Driver (1997 Cummins 12 Valve).

What is the minimum that I will need? Just the crank and pistons? I've seen the build list, but I've also seen people just swap crank and pistons and have it run just fine so I'm thoroughly confused.

Orange 94 · Dec 8, 2013

First off, welcome to the forum!

Second, I believe [MENTION=10997]g36 monkey[/MENTION] stroked his to 4.3. So he will be the most help

Mine is an actual 4.2 and I've done nothing stroking wise (that sounds dirty).

StoicPanaphobic · Dec 8, 2013

Wait, how did you increase your displacement to 4.2L without stroking? You BORED to 4.2L?

I do know that to stroke to 4.3L you bore it .030" over and stroke it to 4.2L.

And thanks! I enjoy the welcome! The Mustang subreddit doesn't really help, they're too busy *****ing or glorifying the 2015.

Orange 94 · Dec 8, 2013

StoicPanaphobic said:
Wait, how did you increase your displacement to 4.2L without stroking? You BORED to 4.2L?

I do know that to stroke to 4.3L you bore it .030" over and stroke it to 4.2L.

And thanks! I enjoy the welcome! The Mustang subreddit doesn't really help, they're too busy *****ing or glorifying the 2015.

Take this

and put into this

I did the 4.2 v6 swap from a f-150. Its basically the same block as the 3.8, but has split port and more displacement

StoicPanaphobic · Dec 8, 2013

How easy was the swap? I could score a used 4.2L for cheapish. Cheaper than it would be to do a 5.0L swap, well, a correct 5.0L swap.

Man, I can't wait to get my Mustang back from the shop. It's kind of a crappy story on why I have to get it repainted and stuff. :cry:

Orange 94 · Dec 8, 2013

StoicPanaphobic said:
How easy was the swap? I could score a used 4.2L for cheapish. Cheaper than it would be to do a 5.0L swap, well, a correct 5.0L swap.

Man, I can't wait to get my Mustang back from the shop. It's kind of a crappy story on why I have to get it repainted and stuff. :cry:

The swap was okay! Its mostly swapping connectors and fabricating a few parts. The biggest thing is knowing what you need to use for parts, lots of 4.2 and 3.8 part swapping. Most of the information I got from a v6 forums, I think they have switched the forum over to the new v6. So I'm not sure if the information is still there or if its all dead links.

While you're waiting for monkey or someone else to help, you should make an into thread here.

g36 monkey · Dec 9, 2013

The two motors are basically identical, the main difference being the crank. My motor is a 4.2 that is bored 30 over. If you did that it would be night and day to that, as you noted, anemic single port set up

StoicPanaphobic · Dec 10, 2013

So, all I really need to do is swap the crank and pistons?

Edit: I don't really want to do a split port swap, I'd rather do this http://www.supersixmotorsports.com/_pdf/3.8_4.2/SSM2013catrev1IntakeManifolds.pdf

Orange 94 · Dec 10, 2013

Why not split port! Its actually a pretty good upgrade over the singles.

If you want to stay v6, I guess you'll have to ask yourself if you want to build your exsisting motor or do a swap.

For swaps, the two main ones are the 4.2 f-150 or the supercoupe t-bird.

StoicPanaphobic · Dec 10, 2013

Well, I'm pretty much shooting myself in the foot. SuperSix's 99-04 "PowerPak" contains everything needed for a split port swap. Maybe I should look a little deeper before just declaring something! :grin:

g36 monkey · Dec 10, 2013

Honestly, I love Super Six, Tom is probably one of the most helpful guys I know, however, it'd probably be cheaper to get a junk yard f-150 with a blown headgasket or something, take it apart, get it refreshed, and have the heads and intakes ported while there.

Put it all back together, like a brand new motor already ported out. Then, you can throw boost at it and make more power with less psi. Happy all around.

racenmotorsports · Dec 11, 2013

Ok, just curious, what years F-150s do we steal the motor from?

StoicPanaphobic · Dec 12, 2013

Any after 1999 or 2000. I can't remember which one it is, but some of the earlier ones have had a problem and so most people suggest those after a certain year.

Alright, so what you're telling me is get a broken/used 4.2L, refresh it, and port the intakes will those get me 100-130hp gains like the PowerPak claims?

If the gains are the same, I'll skip the $25-30/hp I'd have to for that PowerPak, and do what would be more justifiable.

Also, do I really need to use a WHOLE 4.2L engine? Couldn't I just take the heads, intake, pistons, and crankshaft from one and swap those parts in?

The reason why I'm so hesitant is because a) I have time b) I don't want more parts than I need.

Orange 94 · Dec 13, 2013

StoicPanaphobic said:
Any after 1999 or 2000. I can't remember which one it is, but some of the earlier ones have had a problem and so most people suggest those after a certain year.

Alright, so what you're telling me is get a broken/used 4.2L, refresh it, and port the intakes will those get me 100-130hp gains like the PowerPak claims?

If the gains are the same, I'll skip the $25-30/hp I'd have to for that PowerPak, and do what would be more justifiable.

Also, do I really need to use a WHOLE 4.2L engine? Couldn't I just take the heads, intake, pistons, and crankshaft from one and swap those parts in?

The reason why I'm so hesitant is because a) I have time b) I don't want more parts than I need.

You can do pre 1999. Mine is out of a late 1998, but yes the early 1998 and 1997 aren't as good.

You wont get 100-130hp by porting them yourself. I'm not sure if you'd get 100-130hp with the powerpack either.

My car did 199whp with:

Mild ported split port heads and intake
Comp Cams 259HR115 cam
Comp Cams 26918 valve springs
Scorpion 1.73 roller rockers
94 3.8 v6 stock headers
94 3.8 v6 25% underdrive pulleys
Mac Cat Back w/polished tips
Pacesetter H-pipe
Manual t5
8.8 fox diff assembly 3.73 gears

You want the whole 4.2l, and a whole 3.8. There's tons of parts you need to interchange and you dont want to be search. I'd recommend having the harnesses too.
Use the 4.2 block and everything.

g36 monkey · Dec 13, 2013

Yea, got a whole motor and refresh it. In theory, you can take the crank and rods...but why. I wouldn't just throw a set of used pistons in, but I'm anal about that stuff

StoicPanaphobic · Dec 13, 2013

Thank you guys so much! I'll be on the lookout for a Used 4.2L.

I'll keep you guys updated, if I don't post for a while, I haven't disappeared, it's because I'm in the process of getting my stang back.

Sent from my iPhone using Tapatalk

g36 monkey · Dec 13, 2013

Roger that man

StoicPanaphobic · Dec 23, 2013

Hey guys! The 'Stang is finally sitting at a body shop that is willing to give us an estimate.

I have more questions.

My car is manual, but all the used engines I find are from cars with automatic transmissions, will this be a problem?

Also, does it have to come from an F150 or E150? I find plenty of them from Freestars/Montereys, will those be fine?

Exhaust is another issue, can I reuse my 3.8L headers?

Are all 4.2L split port intake?

Orange 94 · Dec 23, 2013

The transmission shouldn't be an issue. You use the mustang bell housing and tranny. You need the correct flywheel though, 0 balance. Use a newer mustang(01-04?) or the truck flywheel.

You need the f150 or the E series van. The bellhousing bolts pattern are different on the rest.

Yes, you can reuse the 3.8 headers, I am.

Yes the 4.2 out of the f-150 or E-series are all split port.

g36 monkey · Dec 23, 2013

your headers will be just fine. I think 97+ is split port, its easy to tell when you look at it.

You won't have issues, just need to get a flywheel and a clutch set up.

I'm not sure on the freestar question