1965 Engine replacement choices (cheapest)

Go for a SBF 289 and a manual transmission and enjoy it

The easiest is a 289 with the C4 automatic. No adaptors needed, no computers or associated wiring, it is probably the most available in wrecking yards, and parts to modify are found everywhere. WORTH is right about the 200 inline 6 which I have in mine. Some guys who do a V8 swap give them away just for hauling them off. Even with minor mods the little 6 can pass the century mark on the highway and get great MPG.

If I were starting from scratch, I'd go with the roller cam 5.0 (like the 1990 you mentioned) and the T5 it's likely attached to. I tried to give away a 5.0 with about 120K miles (ran fine) but realistic CL ads seem to favor a few hundred bucks for a nice running one. T5's are popular (as in expensive-ish) but still seem to be found for $500 or less. My advice is to find a complete Fox-body that runs, (I've found several for $1000 locally over the past year) and grab the engine and trans, then convert it to carb and mechanical fuel pump for simplicity sake and part out the rest. Probably wind up with a free engine by selling parts.

I put a 289 out of a Mercury Cougar (same as Mustang), put a 303 three speed (full-syncromesh) behind it, with the BIG flywheel from a 4 door sedan, installed 2.79 rear gears turning 29" tall radials, then built the motor for torque in the 2000 to 3500 rpm range. Why? In a light 1940 Ford coupe and built to breathe in-and-out at those rpm's (truck cam (van), cast-iron headers, straight-thru little 24" mufflers, Mallory dizzy with vacuum advance, hot coil (I forget which brand but it would weld your butt-crack closed if you got hit), Autolite 2100 carb, Dupree electric fuel pump, flex-fan, bored .040", and lowered to cut highway speeds wind drag. At 55 to 90 mph...and occasionally above...it would run a hole in the wind getting 25 mpg! Why 3-speed? Gets into high gear quicker. Why 2.79 gears? Slow the engine to where the Van cam works best (makes torque). Why 29" tall tires? Every tire revolution it is farther down the road. Why the bigger flywheel? A mass in motion tends to stay in motion, is a law of physics that applies to motor setup. That flywheel was about 10 pounds heavier than the Mustang/Cougar, and once I got up to speed I just tapped the throttle about every hundred yards to keep it at speed. That is a little over-stated, but not by much. The 289/302 is a fine motor for just about every application.

I like the zookeeper's idea of finding a cheap donor car that runs. You will likely need a lot of little parts like brackets and bolts and things. and maybe bigger ones like a rear or driveshaft. You also get to drive the engine and trans and assess their condition before you buy and remove them. Then after you strip it you can sell the shell and get some money back. The 6 would definitely be a cheap route but in the end, the car will have more value and be more fun to drive with an 8. Was a 6 or an 8 originally in the car ?

Rustaddict is correct about value, but only to a point. Years ago the V8 was a much better choice, but not today. Three of four Mustangs sold originally were V8, which now makes the 6 a more rare choice. One of the Mustang books about 15 years ago listed the 6 as $900.00 less value than the V8, but if the 6 has AC, the value is the same. After I got my 6 Pony I got serious about it and have found much to be said positive about the six. If you plan to upgrade the car no matter the engine, all the special parts are also available for the 6 powered car. I have added front discs, a rear anti-sway bar, polymer bushings in many places, and new rubber bushings in all others, stiffer front coils (cut 3/4 turn), V8 rear leafs (115 lbs compared to 85 lbs), gas shocks at all 4 corners, 15" x 6" wider wheels/tires, and 1" lowering blocks in rear. The V8 adds about 250 pounds to the front of the car, plus 50 lbs. in other places. That makes it front heavy, while the 6 cylinder is much better balanced front-to-rear. With a maximum bigger bore, mild cam, 2-barrel carb, hotter ignition, and better exhaust, the car runs much faster than any US speed limit at well over 100 mph, can canyon-carve with many sports cars, rides nice and gets 25 mpg on the highway. Mine has AC and a modern stereo system, new tinted windshield and many extras. It is a driver I take on long trips and I have never missed not having a V8.

Not to start an argument, but a SBF weighs about 450 lbs where the six is about 75 lbs lighter, not 250 lbs. If it were 250 lbs lighter that would put it at 200 lbs. By comparison the all-aluminum two stroke twin in my Yamaha banshee weighed 125 lbs! The trans for a 6 doesn't weight one ounce more than the trans for a SBF, in fact they use the same C4 if it's an auto. Flywheels weigh the same and an 8" rear and 7.5" rear weigh roughly the same so the previously stated 300 lb overall difference simply doesn't exist. I love all kinds of Mustangs, but if you're looking for decent power in a small package, well there's a reason they never made a Shelby 6 or a 6 cylinder Cobra...

Zookeeper, you misunderstand my statement. The engines weigh about 90 pounds different...I have actually weighed them ready to run down the highway. One of the Mustang magazines also did this and the difference was very close to mine...about 300 lbs. I'll find the article and post it. The added other things needed when the V8 is installed adds up to about 200 pounds. Bigger wheels and tires, bigger brakes and steering components, suspension pieces, etc. add a lot. Most V8 buyers also opted for power steering, which is not needed with the six. If one decides to "round-down" the average to 200 pounds, that is like hauling Bubba around in the shotgun seat...all the time. My numbers are REAL not exaggerations, though they may seem that way. I have owned many Mustangs, my first was a 1967 with 289 purchased NEW. I was at the 1964 Worlds Fair in NYC and fell in love with the new Ford then...almost buying one, but Navy pay SUCKED then. I am 75 years old and built/raced small block chevy and Fords for decades, and I am familiar with their weight. NO DOUBT the V8 is a much better engine to build for racing, but us car guys sometimes overlook why engineers put a 6 in a Pony at all. The inline 6 is better balanced and with 7 main bearings can handle 7,000 rpm. If you think that is impossible, there are inline 6-cylinders in Australia running in the 8's at a full 1320. With an Aussie cross-flow head, big turbo and built right, the 6 can hold-its-own. Go on-line for Australian six racer. Sorry if my statement was confusing. I do not have the OEM title to my other V8 Mustangs, but I am fairly sure they said 2900 pounds, and my 65 six title that I do have, says 2600 pounds.

zookeeper said:

Not to start an argument, but a SBF weighs about 450 lbs where the six is about 75 lbs lighter, not 250 lbs. If it were 250 lbs lighter that would put it at 200 lbs. By comparison the all-aluminum two stroke twin in my Yamaha banshee weighed 125 lbs! The trans for a 6 doesn't weight one ounce more than the trans for a SBF, in fact they use the same C4 if it's an auto. Flywheels weigh the same and an 8" rear and 7.5" rear weigh roughly the same so the previously stated 300 lb overall difference simply doesn't exist. I love all kinds of Mustangs, but if you're looking for decent power in a small package, well there's a reason they never made a Shelby 6 or a 6 cylinder Cobra...

Click to expand...

Do I understand correctly that the C4 between a 200 and a small block will; interchange ?

I think the bellhousing may be different, but they're the same trans. BTW, want to know how I found out 6 cylinder flywheels interchange with SBF? I bought a flywheel that accepted an 11" clutch at a swap meet that was cheap and had "302" written on it with a paint pen. So I bought it, had it surfaced and bolted it on my car. It shook so bad I had double vision at idle. I pulled it back out, compared it with the smaller flywheel I took out and did some checking. Found out the bolt pattern is the same...

The early 65 289 bell-housing had a smaller bolt pattern than the later 289, but the trans was still a C4. Depending on engine-trans combo, the flywheel must be fitted and balanced to the particular engine. Too many years ago but I put a big-car flywheel behind a Mustang 289 and had to make some mods...but don't remember what they were. It seems the crank harmonic balancer and flywheel balance had to match.

This 32 coupe I built in the 70's had a early small bell-housing and later OD transmissions would not fit. Also, my 65 200 six will not work with any Overdrive due to odd bell-housing.

The article I mentioned earlier on 65 Mustangs, was in a "Just Mustangs" magazine from England in 1965. A quote: "When the next larger engine, the 289 is ordered, there is an immediate jump in front-end weight by some 100 lbs. When the V8 is installed the car is automatically equipped with heavier front suspension components, larger tires, wheels, brakes, rear axle and other lesser related components. So there is a net gain of 300 pounds involved." Using that plus my title weight numbers of 2600 and 2900 lbs. I arrived at 300 pounds less for a six. Remember, in Europe road racing is king not drag racing, and 6-cylinder cars are prized over the common 4-cylinder for their torque, needed in up hill running. Believe it or not, they actually praised the 6-cylinder brakes. Go figure.