the 2003 f150 4.2L engine uses the same block as the 3.8/3.9 mustang, its just bored over a little... so my question is how much power can the stock internals from the 4.2 handle?

i found an f150 at a salvage yard near my home and im wondering if it would be worth my time or to any benifit for me to pull the heads and internals (cam/crank/valves/lifters) and intake manifold to use on my 3.9 while i save up to buy merana's 4.2 stroker engine?

 

It's not 'bored over', it has the same bore. It's a longer stroke of the crank. Stock internals handle the same as the stock 3.8L internals can. The heads and lower intake are the same between truck and Mustang. The 4.2L upper is too tall to use - even with a cowl hood.

Don't give any money to Morana. He's known for taking money, not sending parts, stealing ideas, false advertising of parts that have never been made and generally poor products and customer service.

The junk yard 4.2L is a smart choice. Just get the whole motor, and swap on your Mustang upper intake. It's a great mod to do.

 

Does it use the same heads as the 3.9? and how much would it benefit me to do the whole swap? Is it worth the money?

 

3.8L/3.9L are 99.999999999% the same motor. The heads are the same as the split port 4.2L from the F150 and van. They are a good power jump over the stock 3.8L and respond very well to boost applications (supercharged or turbocharged).

 

do you know if the f150 were dual exhaust or single? do you know if it uses two headers or a single exhaust manifold?

 

Anything not an inline motor, example a four cylinder or inline six, is going to have two manifolds, but besides this you will be using the exhaust from your mustang, the exhaust on the truck is going to be routed different on the truck and will not fit your car.

 

i never thought of that.... thank you for the info. The reason i am asking these questions about the 4.2 is i am planning on running the M112 setup from mysteed, and i am trying to get a good base for stage one of my project.... i am currently planning (for stage one) on running the M112 on my stock 3.9 and adding a few bolt ons like exhaust and what not, so i was just curious if doing the upgrade to 4.2 is worth my time and money.... my end goal stage one is 275-295 rwHP.... for stage two a couple years down the road i am planning or rebuilding my engine with a 4.2 forged stroker kit and running higher boost, end goal 450-500 rwHP daily driver. I have no 1/4 mile plans for this car, just a fun drive.

Any one have any ideas or input for stage one? prefferably low cost as PFC's dont get paid that much.....

 

I'd buy a 4.2 and build it up out of the car and mount the supercharger on that, it will be cheaper and faster that way.

Build straight to your end goals, your spending a lot of extra money to do an engine 2-3 times like that.

 

^ Agreed. I'd get the 4.2L and build it up outside of the car and leave the working stock 3.8L untouched while you do it.

 

anyone know where i can get a 4.2 forged stroker kit? i know the have em at morana and supersix, but any cheaper ones out the?