fanaticstang15

Hello everyone! Im relatively new to the forums and I have been looking through all of the old posts on this subject and I have found ALOT but most of it covers a swap with an old f-150 engine. There isnt a whole lot on taking the stock 3.8 and converting it to a 4.2. From what I've read, all I really need for my '96 is a 4.2L crankshaft, the rods, and possibly oversized pistons, I was wondering if there was anything that I was missing. Also, is there any gain in swapping rather than converting?

~Ryan
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indisposible_teens

I would rather do the swap than a conversion. I was thinking about doing a split-port swap to my single-port but then I rethought my decision. If you do the split-port swap to a single-port you are supposed to make a little bit more power than the split-ports do because the single-ports have 'slightly' more agressive cam. The only problem is that more often than not the single-ports are starting to get higher mileage on them. So I would have a H/I swap but would still have the 100k miles on my stock bottom end. I decided that I would rather just swap an entire split-port motor in with lower mileage all around.

It would be the same way with trying to do a single port swap to a 4.2L. Not to mention you would still have to do the split-port swap. It would be much easier to just do the entire engine swap rather than taking your engine out of your car, tearing it down, replacing all of the little parts and making sure you don't **** anything up, putting it back together again, and then putting the engine back into your car. I would rather swap an engine than try to tear my only engine apart and put it back into my car.

03sixbanger

I just got a shortblock from an f150 and swapped it in.....VERY easy swap....well worth the trouble...go for it!!

MustangMike2001

Yeah and didn't your engone blow up like a day later lol I'm jk

03sixbanger

yes it did. just make sure some dipsh!t didnt put your rods on backwards and you should be fine lol

l_shizzle_l

You do not need new rods, the 96+ 3.8 rods are exactally the sameas the 4.2 rods. But why not go forged? You willmore thanlikley need oversized pistions on a motor from 1996. You wil also need a hone/bore on the block and balance the new rotating assembly. Not to mention new gaskets all the way arround.

NeoTokyo

The block is exactly the same, most everything is the same except the crank which is a Steel peice that is very strong. The windage tray is also lower if I recall correctly and the oil intake tube goes down further. I beleive using an 04 Mustang oil pan makes everything clear, and you have to use the 3.8L pickup tube from your mustang.

Now as for Singleport VS plitport.... Well out of the box the splitports beat the singleports on the intake side while the singleports flow better on the exhaust side.

Both respond well to porting THOUGH the splitport is mildly limited to porting on the intake side due to the double runners which make the casting's thinner.

Ported side by side the Splitport still performs better even though its exhaust does not flow as well as the singleports even when ported.

According to a rebuild catalog of mine the cams do not change, though these are replacment cams and could be a generalized grind.

Horsepower Ratings.
94/95 Singleport = 145hp
96/98 Singleport = 150hp
99-00 Splitport = 190hp
01-04 Splitport = 193hp
97 F-150 Splitport = 210hp
98-99 F-150 Splitport = 205hp (it was competing too closely with the 4.6L version which was 220hp)


Hope that helps a little.

fanaticstang15

Thanks for the help guys that definatly answers my question!
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MustangSN95D

what year 4.2 should be interchangeable with a 96 3.8 ?

samiamthemustangman

97-08 But the upper and lower intake have to be changed unless you want to follow Stewerds engine build and have a high enough hood.