stangsnort

I'm new to all this (not working on cars but forums) I wanted to get input from some guys who have done this swap. Although I'm a body guy I do have some knowledge when it come to building a motor.

Things you would have done differently
If its worth it or just spend more money and get a better set of heads etc...

My stang is a 96 with a DOHC is there anything I'd have to change going to a SOHC head? I was reading on build, the guy had his PI head ported polished and added a mild cam and intake and was putting 412hp to the wheels.

Bottom line I wanna read and hear from as many builds as possible so I know I'm making the right build and to avoid common mistakes that sorta thing, Thanks!

JC316

You sure it's a DOHC? NPI means a SOHC head from 96-98, PI means a SOHC head from 99-04. If it is, you definitely want to keep the 4V engine, way better platform. Not buying that ported heads, a set of cams, and an intake is putting 412HP to the wheels. Even with trickflow heads and an aggressive set of cams, you will be lucky to see 350 to the wheels.

First things first, take pics of your engine, lets see what you actually have.

stangsnort

http://www.allfordmustangs.com/forum...ap-407-hp.html

he claimed 407hp my bad.

I know it is a DOHC I've had a few buddies and mechanic verify it, but I cant get pics of it posted for a while cause I'm stationed in NC and my car is back home in WA won't have her till April...that being said what would you suggest on a build? I'm not interested in a supercharger turbo etc...just naturally aspired power mainly heads and cam nothing too crazy

Stevo86

Like JC said, keep the 4V heads. They will flow better than the PI heads. If you want lots of N/A power you're gonna need to tear it down and bump the compression up with some new pistons. While it's apart have the 4V heads ported and throw in some cams. You'll be looking at some good N/A numbers after that.

LilRoush

If you have a DOHC (Cobra motor), you don't have the old school Non-PI heads which are SOHC. You are already about 5 steps ahead when it comes to air flow into the motor. Swapping to the PI heads would be a down grade.

Which does your motor look like:

SOHC 4.6L



DOHC 4.6L

JC316

From what I am seeing, he is speculating that you can make that kind of power, he didn't actually make it. Looks like he made 375HP and 350ftlbs of torque. On top of that, he is doing an engine dyno, meaning no accessories or drivetrain installed. Once you get that on the ground, things change big time.

If you want NA, it's going to cost you more and you will make less power than a supercharger. No offense, but some people are morons when it comes to these cars, I have seen several people think they have DOHC engines when they don't. If you do have the 4V, it's a much better platform to start with.

stangsnort

Well it looks like its a SOHC for sure...I was told DOHC and just believed them and never looked into it further. Thanks tho shows how gullible of a 15yr old I was haha

Since it's a 2v SOHC would you suggest the PI swap or is there something better that's not as common?

Well my car has 120k on it if I put on a supercharger or turbo wouldn't I need to rebuild the motor with forged pistons new bolts crank performance gaskets etc? what kind of boost can a 4.6l that's not been rebuilt handle vs one that has? and what would I be expecting to see in terms of torque and hp? main reason I wanna stay N/A over boost is it's my only car so once I get it here it's my daily driver and I don't wanna see my mpg turn to gpm I know turbos don't run constantly but I know how I drive and it would be, and I know my mpg will go down no matter what I do but main thing I just wanna get more power and not thru a bunch of expensive bolt-ons only adding a lil here and there. Since I'm going to go thru the work money and time I wanna get my monies worth and notice a real difference.

JC316

That is what I figured. The PI swap gets good power for pretty cheap, the Mark VIII swap gets good power for pretty cheap and a supercharger gets great power for not as cheap.

General rule for the 4.6L is that the stock internals are good to 400-450RWP, any more and you are asking for trouble. If you were to just add a supercharger and a PI intake to the stock NPI, you would see a massive increase. Supercharging is definitely the easiest option, PI is the cheapest.

So figure prices and power:

PI swap - $300 for parts, $800 for labor and you will go from 215HP to about 275HP at the flywheel.

Mark VIII swap - Prices vary, but $500 for parts, $800 for labor and you will go to 300HP at the flywheel.

Supercharger - $2000 for parts, $500 for labor, and go to about 350HP.

Prices and labor may vary, if you can do the work yourself, it gets much cheaper. I did the Mark VIII swap for $500 with a new clutch too.

stangsnort

thanks for the info the mark viii sounds like a better bet I mean why not spend the extra money but that's the same head as the cobra, isn't it?

JC316

Almost, yes. There are a few subtle differences in the heads/cams/intake, but it's basically the same. The Mark VIII LSC made 290HP/290Tq through an exhaust system that is like a straw, the Cobra made 305/300.