Crown Vic IFS Questions

[68 Ford Stepside]

The more I read about this conversion, the more I like the idea. Question #1 - Just how low does this conversion lower the front of the truck ? I would still want to be able to use the truck as a truck. Question #2 - Does the engine sit at about the same height as it did before, in other words will it be fairly easy to phase line the engine & trans back to the rearend ? Question #3 - What year Crown Vic's are more suitable for this conversion ? The scrap yards around here are crushing all cars within a couple of days after receipt. If the price was right, it probably wouldn't be a bad idea to buy a couple of these units & store them for future use, I would think. Thanks, Have A Great Ford Day!

[ultraranger]

The more I read about this conversion, the more I like the idea. Question #1 - Just how low does this conversion lower the front of the truck ? I would still want to be able to use the truck as a truck. Question #2 - Does the engine sit at about the same height as it did before, in other words will it be fairly easy to phase line the engine & trans back to the rearend ? Question #3 - What year Crown Vic's are more suitable for this conversion ? The scrap yards around here are crushing all cars within a couple of days after receipt. If the price was right, it probably wouldn't be a bad idea to buy a couple of these units & store them for future use, I would think. Thanks, Have A Great Ford Day!

I have a 2003 CV front suspension sitting in my shop awaiting the time it will be installed under my '69 F100 Ranger. You can expect an average of a 4" drop (give or take).

Only a 4.6L or 5.4L engine will bolt directly to the pedestals cast into the aluminum cross member. Any other engine installed will require fabrication of engine mounts. Your mount design will determine how high (or low) the engine sits.

Civilian Crown Vics ceased production in 2009. P71 Police Interceptor Crown Vics ceased production in 2011. So, the year models needed for this conversion would be 2003-2009 civilian CV or 2003-2011 P71 PI Crown Vic. Additionally, the Mercury Grand Marquis, Mercury Marauders and Lincoln Town Cars of the same vintage also have the exact same front suspension assemblies.

The only difference between the civilian Crown Vic suspension vs. the P71 suspension is the rating of the front coil springs. The P71 has stiffer springs. Initially, I was looking for a P71 setup but couldn't locate one locally. I decided to get a civilian model instead. My reasoning was the civilian model would probably ride better with less stiff springs and the main fact that a civilian CV wouldn't likely have had as hard a life as a police vehicle suspension would have.

There's also the issue of the rear end. Unless you swap out or modify the rear end, you will need to carry 2 spare tires. The Crown Vic's lug pattern is a 5-on-4.5" pattern. Your current rear end's lug pattern is 5-on-5.5". There are a number of options you could take; have the current rear axles/drums re-drilled for a 5-on-4.5" lug pattern, install an '80-'83 F100 9-inch rear which has the correct 5-on-4.5" lug pattern and wider width to match the wider width & lug pattern of the CV front suspension, or install a CV 8.8" disc brake rear end assembly or swap in an '89-'97 Thunder Bird/Cougar XR-7/Lincoln Mk VIII IRS disc brake rear end. --In the case of the IRS rear end, you would have to re-drill the hubs/rotors for a 5-on-4.5" lug pattern or swap to '03/'04 Mustang Cobra hubs. The IRS rears (except for the '03/'04 Cobras) have a 5-on-4.25" lug pattern.


Lifting the 2003 Crown Victoria front suspension out of the back of the '69 F100, after I got home with it. --Thunder Bird Super Coupe IRS shown sitting in the bed (3.27:1 ratio w/ Traction-Lok differential).

[68 Ford Stepside]

Thank you very, very much Steve. I really appreciate the effort you put into an answer to my questions. You mentioned the IFS is wider. Does that mean any inner or outer fender preparation to keep from dragging when turning ? Thanks again for the info. Have A Great Ford Day!

[ultraranger]

Thank you very, very much Steve. I really appreciate the effort you put into an answer to my questions. You mentioned the IFS is wider. Does that mean any inner or outer fender preparation to keep from dragging when turning ? Thanks again for the info. Have A Great Ford Day!

I haven't installed my CV suspension yet, but there are several on this site that have and I haven't heard any of them say they had contact issues between the tires and the wheel openings.

You will have to run later model Ford or aftermarket wheels. You would need to run at least 17" diameter wheels but many run 20s. The 2001 SN95 17" 5-spoke Bullitt Mustang wheels (5-on-4.5" lug spacing) look nice and have a lot of backspacing to them --stock Bullitt wheels are 17" x 8" with 5.72" of backspacing. There are also aftermarket versions of this wheel in greater diameters and increased widths. But then, there are a lot of wheel choices for this setup.

...to me, the Coys C5 5-spokes look the best.


Examples of (aftermarket) Bullitt wheels:

http://www.americanmuscle.com/bullittwh ... No%2BYears

Examples of Coys C5 (I like the Gun Metal Gray wheels)

http://www.coyswheel.com/coys.html



...and a photo of a nicely done (Lincoln Mk VIII) IRS install in a Ford pickup ('88 model F-150)

[rusty63]

I recall reading that build - but it's been ages. Do you have a link to it handy?

[ultraranger]

I recall reading that build - but it's been ages. Do you have a link to it handy?

I'm not sure if you're talking about the IRS installation, but if so here's a link (the guy goes by the name 'Sportruk');

http://www.nloc.net/vbforum/gen-1-light ... rucks.html

[rusty63]

I thought I read it here or FTE… I wonder where he got that tank. It looks cool.

[ultraranger]

I thought I read it here or FTE… I wonder where he got that tank. It looks cool.

The IRS, in the photo I posted, is in a 1988 F150. That is the stock tank for that model with dual (forward and rear) gas tanks. Capacity of the rear tank is 19 gallons. (front tank capacity of a short bed from that era would be 16 gallons and front tank on a long bed is 19 gallons).

The rear tank, from a Bronco of the same era --'87-'89, is 32 gallons.

Part number for the 19 gallon rear tank is Dorman 576-120.

http://m.summitracing.com/search/Produc ... del/F-150/

...not sure what the frame width is on the '87-'89 F150, but if that tank would drop between the frame rails of a 5th generation pickup...

[DHill42]

I am currently working on putting a 2003 CV front suspension in my my wifes 70 F100. I am trying to to figure out what wheels and tires i can run. The truck has 235 65 r15 on it now. I am shooting for 2" of drop and was looking at 17"x9" wheels with 4.5" of back space. I was wanting to run 235 55 17 tires. With the 2"of of drop will the combination rub the finders? If so what rims should i run to avoid trouble.

Thanks for the help in advance!

[Rucksta]

I have a '71 F100 and recently installed a 2003 CV front end and 1998 Explorer rear end.
Benefits: Truck lays-out on the frame, disc brakes on all four corners, improved steering/handling, and same bolt pattern all around.
Drawbacks: Relocated engine mounts and fabricated tunnel for steering knuckle. Minor engineering on rear end to accommodate air bags.

These items (front and rear ends) are readily available... I'd recommend grabbing one when you can to set-aside for the job (i.e. I found a CV that had been rear-ended and an Explorer that had a blown motor).
Good luck

[BlueOvalDave]

I've done one as well a while back. While it does ride and handle nice, as opposed to 1967 era twin I beam tech, I dont like the fact that I've limited myself to certain wheel choices. Mine came out of a 2005 Chicago squad car, so it had the heavier duty springs and I think the sway bar may be somewhat larger in diameter. I think the brakes may be bigger too, but I could be wrong. I work for the Dept and talk to the guys in the motor maintanance division and one thing they told me to watch for was the fact that the aluminum crossmember has a tendancy to develop stress cracks in the center between the mounting pedestals. So I would be aware of that if your looking at squads that came from a large dept ( where we have a tendancy to drive them hard) or taxis. The crown vic front clip is readily available in the bone yards here. I made a engine mounting cradle for mine when I had the 331 stroker in it, I now have a 98 Mark VIII 4.6 and with a little modification to 2005 crown vic mounts it drops right in.

I'm still doing a little research to see if I can find different control arms and spindles that will adapt to the Vic that will allow me to run 15 in old skool rims. I just dont like the ridiculous offset that your forced to use with the vic.

If I cant do that, my vic set up will be for sale and I'll go Mustang II

[luke-ao]

Can the 'front rotors' be re drilled for a 5 on 5.5" wheel?

[elgemcdlf]

Can the 'front rotors' be re drilled for a 5 on 5.5" wheel?

You will have to buy wheels with a min D of 16". Now you are buying (4) 16" wheels with the custom bolt pattern in them. Read that as custom wheels which translates into money not to mention the alteration you have made to the front hubs & rotors.

[luke-ao]

Holy crap, I'm trying to still use my old centerline wheels that have always been my favorite for these old Fords. Not to mention I have brand new rubber with less than 100 miles on them. No options for 15" wheels?

[BlueOvalDave]

yes, as in my previous post, Mustang II