And value is just what the fresh engine will bring to your used 'Stang. If you do the job right, this kind of upgrade should bring years more enjoyment to your classic Mustang.
On The Dyno
The last two miles our 198,062-mile stock engine made were on GTR's chassis dyno. It put out an excellent 207 hp to the tire. Helping factors were underdrive pulleys and precious little internal engine friction. It was, you might say, well broken in.
Don't let the power fool you, however. The old engine burned oil like a steamship smokestack-when it wasn't pouring out of the front crank seal and oil level sender-plus the oil pressure was dangerously low and wavering with rpm. It was surely ready to spin a bearing. Moreover, it was with one part per million from passing its next smog test.
Latemodel Restoration is a...
Latemodel Restoration is a godsend for vintage Fox builds. The company supplied endless parts for our 5.0 interior work; for this engine project, we bought a new engine fan, radiator tank, serpentine belt, and battery cables. Typically 5.0 fans are cracked and ready to fail by now, and the radiator tanks are stained nearly opaque. The belt and cables are maintenance items; we especially wanted stock cables to avoid the bargain-store look of crimping our own cables.
Ford Racing's M-8005-C aluminum...
Ford Racing's M-8005-C aluminum radiator was already on our wish list both to give us a fresh, unclogged heat exchanger, but also extra cooling capacity for both our hot desert climate and higher powered engine. We found it necessary to bend open the radiator support's lower flanges to get the radiator fully seated (a two-minute plier job). FRPP also says to bend the stock upper retention brackets but we used a vastly better Steeda mount instead. Fitting the stock radiator shroud to this radiator is a pure fabrication job. You'll likely drill a couple of small holes in the shroud to relocate its mounting bolts to keep the fan from hitting.
A new crate engine without...
A new crate engine without a fresh flywheel and clutch is like buying shoes with no laces. Again, FRPP has the hot setup in its M-7560-C302N King Cobra clutch kit. A new release arm is typically needed because its throw-out-bearing spring retainers are either broken or too loose to work; because the clutch fork is not part of the clutch kit, you need to order one separately. It's the same with the clutch cable. Use an OEM Ford cable for the later Foxes for maximum durability. Ricardo says the release arm issue is a common "gotcha" on weekend, do-it-yourself clutch jobs, so he keeps them in stock. Something else you absolutely need that no one mentions is an M-6397-A302 dowel-pin kit for the flywheel.
Our new X302 bumped the needle to 270 hp tuned with 13 degrees of initial timing and the fuel ratio leaned to 12.6:1. That seems under-achieving compared to the advertised 340 hp, but not really. Ford rates these engines with a carburetor, short-runner intake manifold, and long-tube headers. At the tire, 340 flywheel horsepower would be 289 rwhp, and you still need to subtract a bunch for the long-tube headers and short-runner intake.
Looking at it the other way, Ricardo says he typically sees 280 rwhp for a street-legal "head, intake, and cam" 5.0 such as ours. Swapping back to our underdrive pulleys would put an additional 10 hp on the clock, plus a couple more for a K&N air filter and cold air intake, and maybe a touch less fuel for 282 rwhp. (We have a paper filter and stock rubber inlet hose.) Either way, that puts our X302 right where it belongs, and it will only get better with more break-in miles.
Speaking of break-in-our X302 had just 603 miles on it when dyno'd. We're sticking with mineral oil until 3,000 miles. That's Ricardo's normal recommendation before switching to synthetic.
Edelbrock supplied its excellent...
Edelbrock supplied its excellent Performer RPM II intake and 70mm throttle body and EGR spacer. These are CARB E.O. numbered parts, which is important to us, and prior testing has shown this is a good bolt-on 5.0 intake. The intake is available in light gray/aluminum or black, and you can see how we rolled. You'll need to either reuse your original intake bolts (more parts to clean) or get new ones. The RPM II does not provide a mount for the 5.0's two bulky electric harness connectors as the stock intake does, so stuffing the harness connectors under a rear intake runner and tying them in place is necessary.
Intake manufacturers typically...
Intake manufacturers typically don't supply gaskets with their intakes, so you must obtain these separately. Stock gaskets are trimmed too small to work, and of the aftermarket gaskets, the popular Fel-Pro 1262 just fit the GT-40X's big intake ports. You definitely want to have these gaskets on hand or they'll hold up your installation in a hurry.
With the engine compartment...
With the engine compartment thoroughly cleaned and our X302 dressed with headers, lower intake, thermostat housing, oil sending unit and so on, the big moment arrived. Dress the engine as fully as possible first because it is so much easier than in the car. Note again how we never removed the hood; there's no need, and there's no safer place in the shop for a hood than on the car.
Even at these most conservative numbers, our X302 gained 63 hp over our original stocker-you could say it really gained 73 hp if you account for the underdrive pulleys. Even better, we were expecting to decisively lose bottom-end torque, but really didn't lose that much. The numbers wander back and forth between the two engines below 3,300 rpm, and you can squeak the numbers by playing with ignition timing, so we're calling it nearly a draw to that point as the area under the torque curve about evens out.
Above 3,300 rpm the X302 simply soars away from the old 5.0 in both power and torque. All said, great results for a crate engine that's less expensive than rebuilding the old engine!
Ricardo installed the engine...
Ricardo installed the engine first, then the bellhousing and transmission. It's a great procedure allowing maximum working room. In fact, we might remove the transmission on future engine jobs even if we wouldn't have to otherwise because setting the engine was so easy without the bellhousing and input shaft in the way. Another advantage is the ground strap at the rear of the left cylinder head is dead simple to reach from under the car, as seen here.
There's nothing tricky about...
There's nothing tricky about installing Ford Racing's M-7003-Z transmission, especially when you have a transmission jack! All connections are simple stock hook-ups and take little time. Because the new transmission is supplied without a bellhousing, you'll need to swap on your old one. Bolting the bellhousing to the engine first, then sliding the transmission into the bellhousing worked great for us.
Two quarts of Royal Purple...
Two quarts of Royal Purple synthetic trans fluid went into our gearbox. Ricardo uses Royal Purple, saying the synthetic seems to offer a little easier shifting, especially when cold.