Panther Headswaps
By: John Gislason (JohnG)

This paper’s purpose is to outline what is involved in changing cylinder heads on a Ford Panther Platform vehicle. Many of the procedures will apply to other vehicles as well, but that determination is at the discretion of the owner. In May 2002, I began a project to remove the stock cylinder heads from my 1999 CVPI and replace them with a pair of Ford SVO cylinder heads for the 4.6/5.4 modular engines. The entire project took about 19 hours start to finish, excluding extra work on the inlet and exhaust manifolds, and the “port matching” of the cylinder heads with the associated clean-up of the debris. The method outlines below is HIGHLY recomended because it is critical that the head gasket surface on the heads not be marred, nicked, or scratched in ANY way, no matter how slight or you WILL fail the gasket. So complete engine removal is a “safer” method than an “in chassis” swap. The time is nearly the same in either method.

Tools & Equipment:
Following is a PARTIAL list of what you will need to perform this “mod” yourself. The credit card goes without saying.
  • Complete set of combination wrenches, Metric 8-19mm
  • Complete set of 3/8” drive socket set, Metric 6-19mm
  • good 3/8” “swivel” or “u-joint”
  • 3/8” drive Tq wrench (0-50 ft-lbs preferred)
  • 1/2” breaker bar, 4” extension, and 15mm socket (for torquing headbolts)
  • 1/4” ratchet and 10mm socket (for starter bolts)
  • 1/4” nut driver
  • 5/16” nut driver
  • 9/16” box-end wrench for torque converter bolts
  • medium size side-cutter
  • good floor jack
  • good pair of jack stands (minimum 2 ton capacity EACH)
  • engine stand (750 lb cap) with 4 “M12” bolts long enough to fit thru the engine stand legs by about 1/2”
  • engine hoist (1500 lb cap) w/ full casters and 2 pt. lifting chain/sling
  • 2 wood timbers, APX. 12”x 6-8” x 4-5” (LxWxH)
  • length of rope (1/4” dia is good)
  • two catch pans for Coolant and oil
  • bolt grip harmonic balancer puller (3 way)
  • “spring lock” tool for fuel lines
  • wet/dry vacuum
  • fender cover(s)
  • supply of “rags”, LOTS

  • Pair of cylinder heads of your choice
  • Left and right cams with followers and lash adjusters
  • 12 qts. 5W-30 engine oil
  • 2 oil filters
  • water pump
  • Throttle body gasket
  • Two to Three gallons pure antifreeze
  • Thermostat and “o”-ring
  • “Head changing kit” (FRPP# M-6067-D46) ~$125
  • Small tube of oxygen sensor safe silicone sealant
  • two exhaust gaskets (cat flanges to exh. pipes and new bolts too)

  1. Use three front cover bolts with the “bolt grip puller” to remove the harmonic balancer/crank pulley
  2. Do NOT support the vehicle on jack stands, but rather by solid timbers under the front tires
  3. Use a single jack stand under the transmission bell housing to support it with the engine removed
  4. Use a length of rope to tie the exhaust to the driveshaft (with dual exh) when removing cats
  5. Remove the catalytic converters complete, yes it’s a pain, but WELL worth it.
  6. After removing the water pump, use the wet/dry vacuum to suck the remaining coolant from the left and right side block cavities.
  7. Loosen the lower front P/S bolt before the other three, trust me.
  8. The P/S pump and A/C compressor can be left where they are, they will nicely lay out of the way, but don’t forget to disconnect the A/C pipe support on the right side cover near the top.
  9. Leave the wire harness attached to the engine
  10. Leave the exhaust manifolds ON
  11. Leave the oil filter, adapter, and if equipped, the oil cooler lines attached to the engine (remove lines at cooler bundle).


Begin the process by draining the coolant from the petcock on the radiator (lower left side), disconnecting the battery, and disconnecting the engine and transmission harness connectors below the brake master cylinder. There is also a harness connector above the bellhousing on the left side, this will be accessible from below after the cats are removed.

Main PCM connections, left side

From above, remove all the battery connections at the battery and rt. inner fender ground, and disconnect the two harness connectors on the inner fender just behind the battery, pull the harnesses free and drape over top of engine. There should now be no wires running from the engine to the car near the battery. Disconnect the two fuel hoses using the appropriate “spiral-loc” tools. Remove the (13mm) motor mount bolt below the Rt. exhaust manifold about 1/2 way back. Disconnect any sensors or valves fixed to the firewall, and disconnect throttle and cruise cables, lay them over to the left side. Remove the inlet piping as an assembly (airbox to TB complete). Remove the upper radiator hose, heater supply hose at the intake (rt. rear corner), and the heater return hose at the firewall. Next, remove the wiper motor cover and drip pan complete (on pre’98 cars) so you can access the upper bellhousing bolts. Remove the top two (13mm) bell housing bolts and any brackets. Disconnect both oxygen sensors. Now remove the fan(s), deaeration tank, and fan shroud from the radiator. Loosen the lower radiator hose clamp at the water inlet, and remove the hose placing it aside. Remove the P/S reservoir (13mm) from the front cover, and tie it upright loosely to the upper radiator hose neck.

Fan, shrowd and FEAD removed

From the front, raise the vehicle, placing sturdy timbers under the front tires, and close the radiator petcock. disconnect the A/C clutch connector, and remove the three (10mm) securing the compressor to the block, lay it gently to the side. Remove the (13mm) motor mount bolt from the front using a long extension. Remove the (10mm) bolt securing the P/S line to the oil pan rail (if equipped), and remove the four (10mm) P/S pump bolts (lower front first) and the variable assist valve connector (if equipped), set the pump gently aside.

From the rear, remove the electrical connections from the starter and using a 1/4” ratchet and 10mm socket remove the three starter retaining bolts (top one is tricky), and remove from vehicle. Also remove the A/T cooler line bracket from the block (rt. side by starter) Remove the lower bellhousing cover plate (13mm) and using a large standard screwdriver thru the round access hole in the converter housing, bar the engine over to access the four torque converter nuts (9/16”), remove them and push the T/C back as far as it will go (~1/4”). Next, secure the muffler pipe in it’s current location (with dual exh., you can tie the “h” to the driveshaft), and remove the cats complete remembering to disconnect and free the oxygen sensor wires. Loosen but do not remove the two rear transmission mount nuts. Now you can remove the two (13mm) left side motor mount bolts from the rear. Remove all but the lower bellhousing bolts from both sides.

Final removal is done by attaching a chain sling to the left rear (on lower crash bracket stud at top inner rear of cylinder head) and to the upper right chain cover stud. Be sure the chain is secured with suitable nuts. Set the sling so the front of the engine will be about 1” higher than the front when hanging freely (it’s a guess), and get the “hook” on the hoist as low as possible. Using the engine hoist, lift the engine until the motormounts are clear of the brackets by about 1/2”. Go under the vehicle, and place a jack stand under the T/C housing (use a small board to distribute the load), and loosen the remaining two bellhousing bolts. Then slightly drop the engine to allow the transmission to rest on the jackstand. Now remove the last two bellhousing bolts completely, and using your large screwdriver, gently pry the engine away from the transmission. You can now remove the engine from the vehicle, and secure it to the engine stand with 4 bolts.


First remove the waterpump and using a wet/dry vac suck the remaining coolant from the left and right block cavities. Remove the valve covers (10mm deep socket) marking the locations of the “tall” bolts for reference. Using an air or electric “impact wrench”, remove the crank pulley bolt and washer, reinstall the bolt finger tight. Using three timing cover bolts, install the puller to the crank pulley and remove the pulley. Now mark the location of all the “stud bolts” on the front cover in a permanent manner for re-assembly, and remove all the bolts, including the four to the oil pan, remove the cover and the “trigger wheel” from the crankshaft . The next step is to remove the intake manifold/wire harness assembly. Remove the two (10mm) bolts from the stiffening bracket at the alternator, and loosen the front bolt (10mm)for the crash bracket, and slip the crash bracket over the “stud bolt” on the left cylinder head. Remove all intake bolts and remaining wiring connectors on the BLOCK, and drape the harness over the intake assembly. Note: the “COP” modules can remain attached to the intake. Disconnect the EGR tube at the right manifold, and remove the intake assembly with harness from the top of the engine and set aside. Remove all 8 sparkplugs.

To ensure proper and ease of reassembly of the timing components, using some form of spray cleaner, just lightly spray the cam gears, chains, and crank gears. Rotate the engine so that the keyway on the crankshaft is at about 10:30, and the “dimples” on the cam gears are at about 11:30 (Rt), and 12:30 (Lft) Note: the large “nub” on the left cam sprocket will be at apx. 7 o’clock if done correctly. Using some highly visible paint (model paint, fingernail polish, “mechanic’s pen”) mark the right CAM gear to the chain with ONE mark, and the chain to the CRANK gear with TWO marks. For the left side, mark the CAM gear to the chain with TWO marks, and the CRANK gear with ONE mark (see photo example). Now, use extreme caution to keep the RIGHT and LEFT crank gears and chains on the respective sides, and there is virtually NO WAY you can mis-time the engine. Now remove the tensioner bolts (10mm), and the tensioners from the heads (marked L&R). Remove the guide retaining bolts, and the guides, inspect for wear, replace if in doubt. To collapse the tensioners, place them in a vice and insert a pick or small nail into the larger hole to separate the “teeth”, and carefully collapse the tensioner piston fully and seat the arm against the piston, remove the pick/nail and insert it into the smaller hole near the base of the piston bore to secure the arm in the retracted position. You can now remove the chains and crank gears, be SURE you keep them separated and on the correct side (a wire and tag is an excellent idea).

Left cam sprocket marked

Left (inner) crank sprocket

(nub, here at 11, should have been at 7)

You are now ready to remove the heads themselves. You can remove the exhaust manifolds at any time, but while the heads are on and the engine on a stand is an excellent opportunity as often the studbolts are quite un-cooperative. To remove the heads, start from the ends and using a 15mm socket and 1/2” breaker bar loosen the bolts in an “x” pattern working you way to the center. The heads are on guide pins, so they cannot “fall” off the block with the bolts completely removed. Once all the bolts are out, remove the head assembly and set it aside. DO NOT EVER set the head(s) on the headgasket surface, lay them on the intake, exhaust surfaces, on end, or even up-side down, but NEVER on the deck face.

Clean-up and Prep:

Clean-up and preparations for the new heads is somewhat problematic. It is ESSENTIAL that the deck surface be completely clean and dry for proper sealing of the new headgaskets. Using any form of abrasive device is now frowned upon, but few good alternatives exist. I used a good putty knife, cotton rag, and “brake clean” to remove about 90% of the junk from the firedeck on the block, then used my palm sander with 400Gr sandpaper. I know, the grit. What else can you really do? The deck MUST be perfectly clean and dry. A “fingered” prep-disc is another possibility, if you can find them locally. There is no grit with them as they “erase” the foreign material instead of wearing it off. Careful use of a rotary wire brush may also be one method of avoiding abrasives. It is highly recomended that the headbolt holes be cleaned out using compressed air to be sure no liquids or foreign material has accumulated in the holes. Use some form of residue free cleaner and a lint-free cloth to give the deck a final wipedown, then cover with a clean sheet until ready for assembly.

The cylinder head deck surface MUST BE ABSOLUTELY SMOOTH. There is NO room for error here, this CANNOT be stressed enough. If the heads are pre-assembled (most are), carefully clean the cam gears and mark the new cam gears EXACTLY like the old gears for timing purposes. COUNT TEETH and transfer your marks, do NOT remove the marks on the old gears until you are SURE everything is correct and the engine is running.


Position the new cam gears in the same orientation as the old ones were when removed, install the appropriate headgasket on the block, and set the new head in place using two NEW headbolts finger tight to assure it stays put. Take ten new headbolts, and put ONE or TWO small drops of engine oil on the bottom 1” of threads, and COAT both sides of the washer, and install finger tight (you will need to remove the two bolts temporarily installed earlier). Following the torque charts, Tq each bolt in order to 30 ft.-lbs, then an additional 90* in order, let sit while you do the same on the other head. Loosen ALL bolts at least one full turn IN ORDER, IN ORDER: reTq to 30 ft.-lbs, Tq an additional 90*, then an additional 90* ALL IN ORDER, EVERY TIME. Note: write the order on the cover rail with a marker.

Once both heads are torqued fully, you can install the chains, guides, and tensioners and begin the final assembly (basically reverse of removal). I did not replace the front crank seal, and it does not leak at all, but I did thoroughly clean the running surface on the crank pulley. Use Oxygen safe silicone sealer at the block-oilpan-timing cover, head to block (timing cover), and timing cover to head (valve cover) locations. You only need a small amount.

Reinstall the engine, make all your connections, and then change the oil and filter the first time. Refill the cooling system, check for leaks, and start the engine. Allow it to run until it reaches normal temp, thoroughly check for any leaks or bubbles in the cooling system. If everything check out OK, change the oil and filter again for the final time. I also replaced the FEAD belt idler pulley and tensioner pulley (same part) as they both had slightly rough bearings.

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