Ford 4.6L DOHC FR500 camshaft kit question

[Daniel Jones]

Anyone here have experience with the normally aspirated 4.6L DOHC Ford V8's?
I have a 1963 Thunderbird roadster clone project that uses a 1998 Lincoln Mk VIII
as a donor (engine including fuel injection, 4R70W automatic overdrive transmission,
front and rear independent suspension, brakes, rack and pinion, air conditioning
radiator, driveshaft, etc.). In stock trim, the 1963 Thunderbird is somewhat
heavier than a Lincoln Mk VIII but after all the swap parts, the Thunderbird may
come in a bit lighter than the Lincoln but it will still be at least 3800 lbs.
I've not checked the final drive ratio yet but the Mk VIII got either 3.07:1 or
3.27:1. I also need to look into the torque convertor stall speed and lock-up RPM.
Given the small displacement and weight of the vehicle, I'll likely swap out the
final drive ratio for something steeper and perhaps change the torque converter for
a higher stall speed but I'd like to get the engine running and sorted before I make
any modifications to the converter or rear end. Car is to be a street toy and will
likely never see a drag strip.

The 1998 Lincoln DOHC 4.6L uses the aluminum Teksid block, "B" DOHC heads, matching
long runner intake and was rated at 290 HP @ 5750 RPM and 295 lbs-ft @ 4500 RPM
with the dual exhaust of the LSC model. I also recently picked up:

2004 Cobra DOHC heads (complete with cams and valve train, very low mileage)
2001 Cobra intake (long runner, cut apart, ported and re-welded)
Mach 1 lid
BBK dual 62mm throttle body (probably overkill for the combo)
JBA stainless steel shorty headers

If they fit, I may pop for a set of the Mk VIII long tube headers from Kooks and I
plan to fabricate a cold air induction of some sort plus I'll need a tuner for the
1998 OBD-II EEC-V. I think the normally aspirated 2003-2004 Mach I used the same
heads and cams as the supercharged 2003-2004 Cobra Mustang. A 2004 Mach 1 was rated
at 310 hp and 335 lb·ft and the parts I have are similar except I'll have a ported
intake with larger throttle body and a better exhaust (no catalytic converters, Kooks
long tube headers, true dual exhaust with Magnaflow or similar mufflers). That leaves
camshafts. The usual upgrade is a pair of '96-'98 Cobra or '99/'01 Cobra intake cams
which have a bit more duration and are supposedly worth 15-20 HP. Cam specs from the
web:

96-98 4.6L DOHC Cobra Mustang Cam Specs:
Intake: Primary Lobe 196 duration (at .050)/ 390 lift
Secondary Lobe 206 duration (at .050)/ 390 lift
Exhaust: 196 duration / 390 lift (at .050)

99/01 4.6L DOHC Cobra Mustang Cam Specs:
Intake: 194 duration (at .050) / 392 lift
Exhaust: 194 duration (at .050)/ 390 lift

Mach 1, 03/04 Cobra, Aviator, Marauder.
Intake: 184 deg @ .050"/0.394" lift
Exhaust: 196 deg @ .050 / .394" lift

However, a local guy has a set of all four Ford Racing FR500 cams:

FR500 (M-6550-T46)
intake: 258 deg @ 0.003" (212 deg @.050), 0.472" lift
exhaust: 254 deg @ 0.003" (208 deg @.050), 0.472" lift
109 LCs (stock cams are supposedly on 114 LSA, can be altered with adjustable sprocket)

Ford claims the cams will increase power through 7000 RPM while increasing low-end torque
and retaining good street manners. A quick 'net search seems to back up that claim, at
least in lighter weight Mustangs with steeper gears. The Ford kit includes camshafts,
valves, springs, retainers and followers. The valves relocate the keeper grooves closer
to the stem tip to accommodate the longer valve springs. The followers also have a
different shape for increased clearance to the spring retainers. The seller only has the
cams. Are there any aftermarket spring packages that will accommodate the extra lift without
requiring replacement of the valves?

Thanks,
Dan Jones

[looper]

Hi Dan,
Not Sure Exactly what Your Question Is. But As For Heads, The B Series Heads Will Out Flow The Cobra Tumble Port Heads, But Suffer From Low Rpm Cylinder Filling And Poor Intake Manifold. Good Up Grade Is The 96 - 98 Cobra Intake And IMRC Plates. Dont Remove The IMRC Plates. Intake Ports Are Just To Big. The Other Problem I Have Seen Is The Secondary Intake Valve Not Getting Washed With Fuel And The IMRC Plate Being Closed Causes Major Build up On The Back Side Of The Valve Reducing Flow.

The 04 Cobra Tumble Port Heads Flows Better On The Bottom (Do To Both Valves Being Used At The Same Time And Smaller Intake Port), And Better Intake Manifold.

Mark 8 Cam And Intake Are Tuned For 5200 And The Cobra For About 6200.

The Mark 8 Uses A Round Beehive Spring And The Cobra Uses An Ovate Beehive Spring Witch Is A Better Spring. Installed Height Of About 1.44, Seat Pressure Of 65 Pounds, And 190 Pounds At .500 Lift. Keep The RPM Under 7000 And The Factory Spring Will Work Fine.

The FR500 Cam Would Be Good, Play With Your Overlap To Get The Idle Quality.

[Daniel Jones]

> Good Up Grade Is The 96 - 98 Cobra Intake And IMRC Plates.

That was the original plan, along with intake cams from the same application.

> Not Sure Exactly what Your Question Is.

Basically wanted to know if the whole FRPP kit was needed when installing
the FR500 cams or there were aftermarket springs that will work without new
valves and followers.

> The Mark 8 Uses A Round Beehive Spring And The Cobra Uses An Ovate Beehive
> Spring Witch Is A Better Spring. Installed Height Of About 1.44, Seat Pressure
> Of 65 Pounds, And 190 Pounds At .500 Lift. Keep The RPM Under 7000 And The
> Factory Spring Will Work Fine.

I knew my '98 Mk VIII had a different spring from the earlier B heads but
I didn't know the springs in 2004 Cobra heads would work with the FR500
cams. That will make the swap cheap and easy.

> The FR500 Cam Would Be Good, Play With Your Overlap To Get The Idle Quality.

I just called the seller and made the deal. Should be picking the cams up
tonight.

Thanks,
Dan Jones

[jsgarage]

Guess your projects to date just aren't keeping you busy enough, Dan? A good reference is Sean Hyland's 2003 edition SA-Design book SA-82 on the 4.6-L Ford engines. Lots of detail, materials used in all the 2 & 4-valve engines to that date, dyno results and what fits/what works, and what doesn't. I assume at that weight this will not ever be a racer....

[Daniel Jones]

> Guess your projects to date just aren't keeping you busy enough, Dan?

Heh, heh, heh. If you only saw the storage building. I've got projects
to last a lifetime. In addition to my own, I inherited a couple from my
dad and my brother's 1937 Chrysler Imperial is all apart in my shop (then
he moved to Florida). Plus I started pulling the engine from sister's
Isuzu Amigo for a rebuild then noticed terminal rust in the frame. A few
weeks later Isuzu settled with NHSTA on frame rust but only in a specific
area so I have to put the car back together and have it inspected for a
possible buy back.

> A good reference is Sean Hyland's 2003 edition SA-Design book SA-82
> on the 4.6-L Ford engines. Lots of detail, materials used in all the
> 2 & 4-valve engines to that date, dyno results and what fits/what works,
> and what doesn't.

There are a fair number of negative comments about that book on the Modular
Ford forums but I'm still considering buying it. Richard Holdener's modular
V8 dyno book is on my list. I've got his 5.0L Ford dyno book and it's pretty
good.

> I assume at that weight this will not ever be a racer....

No, just a street toy. It'll be interesting to see how well it handles with
all that rear over-hang. It's got the Mk VIII air suspension on the front
and I've got the air bags for the back but they aren't installed or plumbed
yet. It just has coils to hold it up for the moment but it's not too far from
being ready to blow back apart and send out for paint.

Dan Jones