Although it was introduced over 62 years ago, Ford’s 289-cubic-inch small-block still has a warm place in our hearts today, probably because of its indissoluble ties to Mustangs, Cobras, and GT40s. If you’re going to tear one apart or try to swap parts, however, there are some running changes you should know about.
This is my garage back in 2014. The 289 on the engine hoist is from my 1965 Mustang, shown in the background; the Mustang is a family heirloom I’ve been working on since 1988, when I was 11 years old. In those pre-Internet days, when I was figuring things out through trial and error, along with a little help from smart older machinists and my copies of Tom Monroe’s How to Rebuild Your Small-Block Ford and Pat Ganahl’s Ford Performance, I realized that Ford was constantly changing little things that could cause big headaches. Here are four of them.
Change L5 (Bellhousing Pattern)
This change kept me from buying a used engine in 1994. With only 61,000 miles on the Mustang’s original 289, pitted valves temporarily cut my driving time short a mere three months or so after I registered the car for the first time (it had been off the road since 1975). I found a 289 out of a 1963 Galaxie that had been running when it was pulled, but it had a block machined for a five-bolt bellhousing (I still bought the cylinder heads for $100 and drove the car over 60,000 miles without doing a thing to them). There is little information about when the change to a six-bolt pattern took place, but the general consensus is that the first six-bolt blocks were cast sometime in mid-1964, meaning that my car was well into six-bolt territory with its March 10, 1965, engine stamp.
Change L7 (Timing Chain and Gears)
This one bit me…hard. Change L7 took place on roughly March 15, 1965, and my engine (as I mentioned) was built on March 10th. Ford changed the entire timing set, so the gears weren’t the same thickness (and, if I recall, the updated thinner cam sprocket had a cast-in “spacer” that pushed it out a little farther than the thicker original). Needless to say, I bought the later set when I decided to change the worn out timing chain when I was in my late-teens or early-twenties. Upon firing up the engine, it was hammering loudly, and upon disassembly, I realized that the fuel pump eccentric was grinding its way through the timing cover. Luckily, the cover is aluminum, so I cleaned it up, found a correct timing set a town or two over, changed the oil, buttoned it up, and went on my way, a little wiser. The difference in the updated timing set fitting or not fitting seems to be the camshaft thrust plate, which was apparently redesigned at Change L7.
Rock Auto’s online catalog shows the differences in tooth width, and you can also see that the earlier set is more than twice as expensive as the later one.
Change L8 (Timing Cover and Water Pump)
Sometime in the late-1965, early-1966 production run, Ford started using cast iron (rather than aluminum) water pumps and an updated timing cover.
These available timing covers once again prove one thing: When you are working on a Ford, you have to do your homework. The later timing covers have a bolt on timing tab rather than the cast-in variety, and it appears that the 1965-67 variety has the upgraded “seven-rib” design that Ford started using after Change L8.
Change L11 (Rocker Arms and Cylinder Heads)
This is a big one that could really ruin your day. Ford changed the rocker arms and cylinder heads because they changed how the rocker arms were “located” on the valve tips.
Before Change L11, cylinder heads had these cast in pushrod guides (and hardened pushrods); therefore, the pushrod acted as the rocker arm locator.
The cast-iron rocker arm was fairly traditional.
Sometime during the 1966 production run, however, Ford started using “rail rockers,” meaning that the rocker arm was centered at the valve tip itself. The cylinder heads were changed where the pushrods entered the rocker box.
Because of this, the rocker arms had to be changed, and after this point, they had “rails” cast into the valve tip end to center the rocker over the valve tip itself. These obviously weren’t used on K-Code “High-Performance” cars because there would be no easy way to set valve lash.
If you want to use roller-tip rocker arms or even the earlier cast rockers with cylinder heads that were cast after Change L11, you have to install screw-in rocker arm studs and add these pushrod guide plates (and make sure you have hardened pushrods).
I’m currently using rail rockers with a set of 1970 351 Windsor cylinder heads on my 289 with a small “RV” cam, but that was only because I was trying to get to the bottom of a valve-noise issue, so I’ve tried several sets of parts I have lying around. You can do that with a small-block Ford, but you definitely have to keep track of the changes that Ford made along the way so they don’t bite you.
Ford continued to make changes to the small-block (a Boss 302 is pictured above) for years after the 289 went out of production in 1968 (50 vs. 28-oz. imbalance, anyone?), not to mention the Windsor, Cleveland, and Modified jumble. You can use later parts on a 289 as I did, but as always, stay diligent!
Sounds like a lot to figure out (pre internet), and even With Internet.
Did I ever mention I was Mainly a Chevy guy?
😉
It was, and I was figuring it out as a fairly inexperienced teenager/young adult. Luckily, by the time I was in my 20s, the Internet was in a pretty good place with some solid advice.
It is truly amazing to reflect on just how much more information is available for those endeavoring to do this sort of work post-Internet versus pre-Internet. Although given the questionable quality of so much that’s available on YT, I have to wonder if having something in print, that’s authoritative (which seems to be the case with the Tom Monroe book you cite), is the best resource. Maybe what the Internet has brought that is most beneficial is the ability to connect with many more people who are trying to work on the same things that you are. Forums and relatively-easily accessible experts are able to bring more perspectives into play…which for a careful reader and critical thinker can be a boon.
Great article, Aaron.
Thanks Jeff. I’d say that the Monroe book is still a great source for anyone building a pre-5.0 era small block. Some things have changed, and the cylinder head options out there add a new wrinkle, but there’s the internet for that.
I’m running 1970 351W heads on my 302 with Comp Cams Magnum roller tip rail style rockers. Handy hint? Ford marine 302s used the D00E 351W heads up thru ’76. Mine were cast in ’75. Looking for a set of these heads? Check your local boat shop, you might get lucky and find a pair that isn’t freeze cracked.
Writing this article reminded me that I kind of want to switch back to the pre-1966 rocker arm on my car. I have two sets of guide plates, one adjustable and one standard. The only pain is draining the cooling system because the screw-in studs enter the water jackets of the cylinder heads, so I like to use some Permatex #2 on the threads. Because the engine isn’t the cutting edge of high performance, I’ll probably use the non-adjustable ones.
Just another job on the list.
In my daydreams I’m regularly rebuilding some mid-1960s Ford hobby car, but I’ll likely never do it in real life. Thank you for taking us through your journey (and leaving a little more info on the Google trail for those who will learn from you).
My Father was working at Ford’s Cleveland Foundry then. I learned from him about production numbers, the date-tag codes, etc.—–all the information cast into a block, head, manifold, etc. that just **might** be useful at some later date .
You’re welcome George…I hope you get that Ford you want. 🙂
Having owned (1) a late 1964 Falcon with a 260 ci V8, and found several inconsistent items both car and engine, (2) a 1966 Shelby GT350 with the Shelbyised HiPo 289 (solid lifters, guide slot pushrods, aluminum hi-rise intake and the R-3259-1 715 cfm Holley carburetor, (3) a 1970 1/2 Falcon station wagon with the emission heads.
1964 Falcon, 260 v8 had 1965 289 heads from the factory, gauges all had C5ZZ (Mustang) PNs, lower front suspension parts were also Mustang parts. Car was built July 27th 1964, so Ford must have updated some parts for the Mustang which debuted in April. Shelby became my daily driver in late 1970, gave my first wife the “family heirloom” diamond engagement ring in it and told her up front not to ever say “either it goes or I do” as I will help you pack. When I had to sell it because we needed the money, she left home while the buyer came to pick up the car.
The 1970 1/2 Falcon was an emission control pig. Poor performance and fuel economy (10 mpg in town). I bought a pair of 289 4V heads (not HiPo), and after some PN research found it had the same cam as the 289 4V non-HiPo. So, a better flowing set of heads, 351W exhaust manifolds, 1969 dual exhaust front H-pipe, 1970 extension pipies, mufflers and tail pipes along with the stock hangers, spark delay removed, cast iron 289 4V intake, car started getting15-16 mpg in town and 20 mpg highway. By the time I finished withe car, it was a well equipt Torino in drag.
Here is the GT350 at a high speed SCCA event:
I would love to have that Shelby (said every Mustang owner ever). 🙂
Now I didn’t have any of those concerns when I started working on my 302 in 1974-75 since it arrived in 1968. Of course the biggest headache for me was the valve train because I was changing out the stock camshaft. Can’t use rail rockers with a higher lift cam as I found out the very next day after the engine was finished. So back into the garage, after being towed home, and off came the heads. I tried to do the tapping for the screw in studs and was successful on one head and cracked the other. The replacement head, from Center City Ford, cost me $35 and I had someone else tap that head. It seems the last issue was finding guide plates for the engine as most all speed equipment out there was for Chevrolet. Finally, with the help of the performance guy at Center City we found them and the engine has been fine ever since. Today the engine runs roller rockers with those same guide plates and hardened pushrods.
I would definitely leave tapping the heads for screw-in studs to the machine shop; that would be an easy one to drill a couple degrees off. Good call on doing that with your replacement head. It’s always tempting to do everything yourself, but sometimes it’s just not worth it.
One of Ford’s most endearing qualities is the tendency to change most any thing at most any time. You have identified the early Windsor ‘revisons’ well, I remember a friend back in the day went through the whole rocker arm fiasco. He had a set of the heads with the large pushrod holes but didn’t have the ‘railed’ rocker arms. The 4.6L Modular/Triton V-8’s are really messy, there are some major differences between Romeo and Windsor manufactured engines. Someone ought to write a book on all the different timing covers those engines have.
I can’t imagine the carnage that would happen if you used regular rocker arms with the ’66-and-later heads. It probably wouldn’t hurt anything but rocker arms and pushrods, but there’s always a chance that an errant rocker arm could dislodge a keeper by ramming into a retainer.
I can tell you what happens. The rocker slides off the top of the valve and then off the top of the pushrod. The pushrod then slams against the valve cover and you hear a WHACK! It will catch your attention and that is just one rocker.
Exactly. It didn’t run for very long!
Given the interest in 1st gen Broncos, the 302 used in the Bronco has a number of unique components to make it fit in the engine compartment. The whole front cover is slimmer, and the fuel pump has “over-under” bolts vs. the normal “side by side” bolts on most small-blocks – and let me tell you, the top bolt is a bear to get out. The water pump is also different, with a slimmer profile to allow enough space between the fan and radiator. A buddy of mine found all of this out the hard way when he rebuilt a used 302 from a truck to put in his 1977 Bronco, without switching all the front-dress components.
Changes to the 302 heads came along in 1979, when they switched to fulcrum rockers, and added an integrated port into the heads for the Thermactor AIR injection system. According to various small-block rebuild books, these fulcrum rocker heads have an improved rocker ratio and enhance low-end torque. Most of these heads will have the AIR port at the rear, which fits fine in most vehicles with enough clearance remaining to get to the metal AIR feed tube should it rust out. There was another variation for the F-series trucks with the AIR port on the side of the head (on the exhaust face) since the engine sat too close to the firewall to accommodate the rear AIR port – apparently these are one-year only heads for the 1979 model year. I used a set of these heads on another friend’s 1976 Bronco that we built up a 302 for, but in the pre-internet era, it wasn’t an easy task to hunt down a set. You may ask, “why bother with the AIR system?” but at the time in Colorado, the AIR pump and related hardware had to be present to pass an emissions test.
I had no idea there were so many changes so early on. As far as I know, that’s rather different than with the small block Chevy,
More fascinating detail info .
I wonder how many buy some old beater 1960’s Ford with a swapped in junkyard engine that needs overhauling .
-Nate
While in the service in the mid-70s I rebuilt many 289s without the advantage of an air scraper. The one thing that sticks in my mind was the intake gasket was an absolute bear to remove. It seemed they were all scraped off in 1,000 pieces. Other than that, a piece of cake.
It’s been so long since I had the intake off for the first time that I don’t remember that intake gasket! An air scraper sounds like a good tool; I just use a razor blade or, if the going gets tough, a carbide scraper.
We used to say that if you were buying replacement parts for a Ford, you’d have to tell the guy at the parts-counter the model year, vehicle model, VIN number, engine displacement, and the color of the carpeting to get the correct rear-axle (or whatever) part.
The problem for Chevy-centric guys like me are that in the years since then, Chevy has made almost all of those same mistakes. Chevy has used round pushrod holes in the cylinder heads, and a stamped rocker arm with the same sort of self-aligning “rails” to hug the valve tip. Chevy used the crazy intake-manifold/cylinder head/valve cover three-way gasketing nightmare from the Ford FE engines on the 60-degree “Chevy” V6 of 2.8L, 3.1L, and 3.4L displacement. The LS series of engines has a somewhat different bellhousing bolt-pattern than the older “Chevy small-block” design. Chevy screwed-up the front-cover and water pump when they went to the “reverse-cooled” LT1 in…’92? And the ’96-newer Small-blocks need a special timing chain and gear set due to GM putting a crankshaft sensor and reluctor behind the timing cover, the reluctor takes up space that forces a more-narrow timing set.
We used to say that Ford’s philosophy was “We’ve already paid the engineers, let’s have them change some stuff!” But then we started working on Japanese cars, and their philosophy was “We’ve already paid the engineers, let’s have them change EVERYTHING!”