Ok my 97 F150 has a 4.6 in it. My truck only came with 210 hp. I need more hp and tq to pull my boat and trailer with. I'm wanted to know what would be the best and cheapest route to go? Should I rebuild the 4.6 and put PI heads with tow cams on it or drop a 5.4 with navigator heads with tow cams on it? Any suggestions will help a lot.

 

What axle ratio do you have on your truck?

 

4.6L with navi heads would make a nice beast but have fun with the tune and PCM... i thought about doing a dohc swap but its alot more work then i want and DOHC doesnt have the low end that SOHC does..

 

I got 4.88 gears in front and rear. I think the DOHC will make more with a tow cam than a SOHC want it? I just want it tow stuff a whole lot better than it does. It starts off good pullen stuff with the gears but when I'm on the road is when it suffers.

 

well the big damn tires on that thing would hurt anything as far as acceleration comes.

 

n the end, a SOHC 16 valve engine would have better torque on the low end where the DOHC valvetrain’s weight results in lower torque. But at high engine speeds, the 16 valve DOHC engine’s peak torque and horsepower would be greater. That’s the trade-off. With the amount of valves being equal, SOHC has better low-end torque because the valvetrain package is lighter while DOHC has better top-end power.

http://paultan.org/archives/2005/06/...c-valvetrains/

 

ok thanks for your help. So should I go with the 5.4 or the 4.6 block? Any more sugestions will help.

 

Faster, I hate to say this this but you don't know what your talking about.
It has nothing to do with valve train weight.
Cam timing is the key. Both engines will make lots of torque if equipped correctly for the application and tuned in the PCM.
Hi rpm power differences however is a different matter but that in not what is being addressed here.

 

i was just going off info from what people have documented online...

 

Well Bluegrass what do you suggest I should do get my truck where it needs to be for towing? Please remimber I would like to get little better mpg than I get. The same will be ok, but better would be great lol.

 

tis hard to get better mpg if u want speed and huge tires with 4.80 gears... its just not gonna happen

 

I don't want speed just more tq and hp. See the engine is straining becouse it does not have the HP or TQ to pull its self. If I get more the engine will be under less strain so I should get more MPG, maybe be not much but every little bit helps. Besides if I was wirried about gas that much I wouldn't of jacked it up and put 37s on it. I at lest want the mpg to stay the same. U know what I mean man?

 

i would rebuild the 4.6 with a forged piston and install a allen/magna supercharger. that will make more low end and power than a regular or navi head. i realize we are are talking some cash, but so is a swap to a 5.4

or you could go the bolt on route and pay as you go. just remeber that most mods are going to increade power in the upper rpm range whicj is not a lot of help with towing.

 

Ok thanks man.

 

How much power do you think if I rebuilt the 4.6 chane the heads to to PI and install a roots blower with 10lbs of boost? What does anyone think about this combo? Or just the same thing with the 5.4?