4.6 heads

[ModMech]

Ok,

1) ALL, and I do mean ALL 4.6/5.4 heads ARE THE SAME, there is NO difference. One head will bolt onto the other block and no one will know.

2) There are THREE "2Valve" head designs (except the motorsport "SVO" heads). a) '91-'95: NPI, large chamber, teardrop intake ports, small valve guide/short lift capacity; b) '96-'00 "NPI": large chamber, teardrop intake port, high lift capacity, large valve guide; c) '99-up "PI": squarish intake ports, high lift capacity, small chamber.

3) When installing "PI" heads with smaller chambers to replace "NPI" heads you will GAIN about 0.9 CR points (go from 9.4:1 to about 10.3:1). This is good, but requires premimum fuels.

4) The intakes go with the ENGINE displacement, however the "PI" intakes flow much better than the NPI ones (aluminum or plastic).

5) There is NO NEED to swap heads on a '96 up engine to get more power. All you need is a set of "PI" cams and a "PI" intake to make the SAME power as someone who did the "full" headswap. You will be close, but not exactly the same because you will have the stock CR of about 9.4, while a headswap will yeild 10.3, so it will make slightly more power.

[thunderbird muscle]

Petis051 Are they performance?

Does anyone know ways to increase horspower by doing things my self ex. Air intake. the only one I know how to do really is the only one really talked about. Thanks for the Help!!!!!!!!!!!!!!!!!!!!!!

If I can help in any way just ask.............

[RavenProjecT]

Originally Posted by thunderbird muscle

Petis051 Are they performance?

Does anyone know ways to increase horspower by doing things my self ex. Air intake. the only one I know how to do really is the only one really talked about. Thanks for the Help!!!!!!!!!!!!!!!!!!!!!!

If I can help in any way just ask.............

There's tons of stuff you can do yourself.... intake/air silencer removal, underdrive pulleys, throttle body/or tb spacer, MAFs, coil packs, plugs/wires, B&M electronic shift kit, headers, and on and on. The only restriction really is time and $$$$.

check the other threads, I answered this same question for you a while back - peace

[thunderbird muscle]

Thanks

I quess I did forget to add cheap.
I already did the air intake, I'm taking off the silencer this saturday

Where can I find the best tb spacer at a decent price at what size should I get

Also does anyone know how to build an airbox for a ram air hood???

Thanks for all the help!!!!!!!!!!!

[petis051]

No there not performance heads. there off a 95 t-bird 4.6 with twin cams. I was looking though for anyone who knew the best way to change motors in a 95 t-bird, 4.6. any tips would be helpfull. I'll keep an ear out tho for any performance parts for a 4.6 tho. Thanks

[thunderbird muscle]

What kind of motor do you want to change to a 5.0?

[RavenProjecT]

there is a kit to convert a 4.6 to 5.0 over at www.modularperformance.com.

[caddy111]

This will give all you need to know. Modular mix and match. Part 1
see it at: www.musclemustangfastfords.com/tech/MixedMatch If you
read all of it twice. Boom, you got your answere. caddy