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Not planning on doing anything until the fall/winter, but I'd like to do my research and plan ahead. Going to pull out my 289 and do "something" to get more horsepower. I know I could drop in crate motor but what's is the fun in that. Looking to upgrade the 289, going to keep the C4 and the 8" but change gears. Need to get the 2:80's out.

Don't know anything about the engine other than it is a C code with the prior restorer put a cobra intake manifold and a Holley 4 barrel. Engine runs nice, great vacuum, just not peppy enough. Plan is for a street engine. This car will never see the strip and I drive it a lot. Don't need high rpm power, looking more for spirited driving from stop light to stop light.

So, if you were going to build your dream 289 street motor what would you do? And while were at it, what would you do to the C4 and what gears would you put in? Just remember, I plan on driving this car around town, back and forth to work (5 miles) 3-4 times a week and as much as I can on weekends.

I'm fortunate that I can spend some money but I don't want it to get so expensive that's its cheaper to drop in a crate motor. Also I know things may change when I get into the motor, but lets assume its a stock bottom end and is not max bored out.

lets have some fun and build me a kick * street motor!>:)
Well, assuming you're going to basically rebuild your existing motor, and do it on somewhat of a budget, then my recommendation would be to continue driving and/or leaving the car alone while you build the replacement, then clean up your existing block/heads and bag them up for safe-keeping. So.... my choice would be:

1. Obtain a used, lower-mileage '97+ Explorer/Mountaineer GT-40P. Many yards will have them still in the vehicles so you can hear it run but, if not, most yards will ALSO give you a guarantee on a good used engine.

2. Strip the motor down to essentially a long-block and sell the left-over components. That includes all the EFI stuff, upper and lower intake, exhaust, ignition system, including crank/cam sensors, pulleys, oil pan and sump and front cover.

3. Inspect the timing chain and sprockets and replace if needed. Obtain the correct fuel pump eccentric (IIRC, one-piece) for a carbureted application and plug the block-drilled oil dipstick hole.

4. Obtain a new Melling standard volume oil pump, pump pick-up and either an ARP or Ford Racing hardened oil pump driveshaft. My suggestion for a pick-up (and oil pan) would be the reproduction B302 piece if you choose to not use your 289's oil pan.

5. For the small cost of a reproduction timing chain cover I'd probably buy new and gasket match the water ports with the block. You'll also need a conversion pulley to mate your Explorer's harmonic balancer with your 289's accessories. In the past you needed to buy a 3-bolt 50oz balancer but now 4-bolt pulley's are available to use with your existing balancer.

6. Using the "clothesline rope in the cylinders" or "compressed air" methods of keeping both valves closed you can replace the GT-40P's weak valve springs, keeping the existing pedestal rockers and pushrods. The GT-40P's factory camshaft, F4TE-6250-BA, is also the same cam used on the roller 5.8 and is a very good "low-end" camshaft for generating torque at low rpm and decent throttle response. While you have the front cover off and should consider it, you could pick up either the stock "HO" cam (I thin the earlier E5ZE-AA works a bit better with carb'd applications) or the "B" cam (M-6250-B303) for a little bit higher rpm operating range. The GT-40P cam is pretty much done at 5,000 rpm but, after all, your motor probably will spend 99% of its time below that anyway.

7. The fact that the GT-40P block as no clutch equalizer pivot boss isn't a factor with your automatic transmission application.

8. I would recommend a Weiand #8020 Stealth intake manifold and a Summit M2008VS500 for carburetion, reproduction HiPo exhaust manifolds, port matched to the heads. DO NOT do any port work on the heads. Confine all your grinding to the header flange. Ideally you don't want any part of the header flange sticking into the exhaust port opening.

9. For ignition, I'd get a new Ford DurasparkII distributor ('85 5.0HO application to get the correct steel gear) and prior to installation send it to Dan Nolan at the Mustang Barn to have the advance curves "blueprinted". Connect the distributor to a Mopar ignition box using the appropriate wiring connectors and pigtails.

10. The only thing I'm NOT sure of is the ability of the Explorer's flexplate to connect to your C4's converter.... I think there are some differences in bolt patterns so you may need a new 50 in/oz imbalance flexplate with the C4 converter's bolt pattern. That's a small expense though.

So, in my opinion... once you sell off the excess stuff and buy new you should STILL have well under a grand into your 289's replacement and it'll feel like you added 100 horsepower.... because you pretty much did.


68 Posts
Yes it is original but its a GT clone so not a high dollar car.
Personally, I'd leave it be and go with a roller motor. You're not going wild with boost or nitrous. So you don't need to worry about the block. In which case, a late model motor will be fine. Then, like I said earlier, the original motor is buttoned up just in case you need it or decide to dell the car.
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