I have a '97 f-150 with the 4.6 in it. The engine has 120,000 miles on it, so i am looking to replace it. Now, i was thinking about building a new 4.6 for it and adding mods to it. But , i want my new engine to have at least 400 hp without a supercharger. I am seriously thinking about putting NOS on it though. My question is, should i go with the 4.6 since i want that much horsepower, or should i go with a different engine? I have $3,000-$4,000 to spend all together (that includes all the extra mods i have to make to the tranny and rear end). I know that i will have to beef up the rear end, but what will i have to do with the tranny? I am plannning on installing the new engine myself to save costs. Also, would a cobra engine fit in my truck? Any input on what i should do would be very helpful.

 

Cobra engine would fit, however, I'd take the cash and put it toward an engine rebuild. The axle is fairly stout, but you'll probably want to get maybe some higher-spline axleshafts. Is the tranny an auto or manual? The manual won't handle power very well, and you'd have to do some serious beefing to the transmission (4r70w) to handle that kind of power. Try www.performanceautomatic.com for that kind of stuff. They have all kind of rebuild kits for most Ford tranny's. $3-4K might not be enough to get you into the 400+ power range now that I think of it. You'd be better off starting with something like a 5.4L crate engine and building it up. One thing is for sure.... don't put Nitros Oxide on an engine with 120,000+ on it... it'll blow that thing in a heartbeat.

Just my $.02
-Flea

 

I agree with Flea, in that you are probably short of funds to get 400hp out of a 4.6. You'd spend that on just a supercharger if you wanted to go that route.

The '97 4.6 was rated at 220 I believe. If your going to build a 4.6 I would say either go with the DOHC Mustang motor, or get a '01 or newer out of the trucks because it has the PI heads. There are others building motors and I think the general concensis is that there is a limit to how much you can get out of the non-PI heads.

If it were me, I would take the 3-4k and put it down on a new truck and continue the payment plan.

 

Just my thoughts --- I don't see how 3-4 k will be nearly enough to build a 400 horse engine. I have a 98 4.6 built up to 300+ horse and know what that cost.

If I were to start over with 400 horse in mind, I would be looking for a 5.4 base motor. I would also be figuring on a supercharger. It is my understanding that the supercharger boost is less stressful on the motor than a NOS kit.

The magnacharger supercharger kit comes with a new 185 ltr/hr fuel pump which you will need regardless. I believe your 97 has only the 85 ltr/hr pump -- very inadequate for any motor producing the power you are looking for.

Bottom line: 400 horse is certainly possible in a 4.6, but not at $4k invested. ( my $.02)

 

I'm sure 400 hp is possible out of a 4.6, but you would spend a lot of money to get there without a supercharger not to mention your gas milage is going to be horendous, and the bigger rear end and whatever your going to do about the tranny is gonna add up pretty quick asell. If I was you, I'd rebuild the 4.6 you have, and go talk to Crash and the guys in the supercharger forum about a MagnaCharger. Even then I don't think you'd be anywhere near 400 horsepower, but you'd have a lot more usable and reliable setup for daily driving then dropping a 400 horsepower monster in there. (in my opinion) As was mentioned, you might consider putting the money your are planning on spending on your motor along with the resale value of your truck and be closer to affording a used L than you'd think...

 

thanks for all of the info guys. I'm not sure what i'll do. But i do prolly want to keep my truck because it is a 4x4 and lifted. I might think about switching to the 5.4 though. Thanks again.