Ford’s Windsor family of small-block engines stands as one of Motown’s biggest success stories. If judged simply for production longevity and numbers, these engines achieve a memorable legacy. Originally introduced in 1962 in a displacement of 221 ci, the Ford Windsor, with its 8.200-inch deck height and compact inline cylinder head arrangement, was a good thing in a very small and lightweight package. The original low-deck Windsor grew quickly through the years, first to 260 ci later in 1962, then gained a 4.00-inch bore for 289 cubes in 1963. Factory displacement in the low-deck engine peaked at 302 ci with a stroke increase to 3.000 inches in 1968, while maintaining the 4-inch bore of the 289. The low-deck 302 configuration would see continuous production until 2001. A longer stroke (3.500-inch) tall-deck version of the Windsor was introduced in 1969, but taller deck results in a wider engine.

Besides its long production run, it is the compact size that still makes this series of engines a favorite. In comparison, the latter mod family of overhead cam engines is nothing short of bulky. When the intended home for the powerplant is the restricted confines of a classic Ford or Mercury compact car, the 302 is a perfect fit.

While these engines produced respectable power in factory form, they did have their limitations. Though Windsor engines proved rugged and durable, a chief limitation was the cylinder heads. Production Windsor heads were far behind the flow capacity of competitive engines of the era. Further, the relatively small displacement also creates a disadvantage compared to other makes with base engines carrying some 50 more cubic inches. Fortunately, both of these shortcomings are easily addressed in a performance build, putting serious power in a small package.

Our project engine started with a production 302 block destined for the restrictive engine bay of a ’63 Ford Falcon. Here, the low deck height of the 302 block allows it to slip into the narrow space between the shock towers of the chassis. Of course, upping the power production would be a major part of the game plan, with Dr J’s Performance heading the build. The factory block received basic machine work, including square decking, a 0.030-inch overbore, and line honing the mains. While this would be a sound basis for a stock rebuild, the goal from here was a hot street combination addressing the shortcomings in displacement, airflow, and camshaft.

Bigger Bottom

There are several popular stroker combinations for the 302, with the 347ci configuration being the most popular. This setup takes the stroke up 0.250 inch to a specification of 3.250 inches. The typical 347 package features an increase of rod length from the factory 5.090 to 5.400 inches, while the compression height of the pistons is substantially reduced. This stroker combination is so popular that items like the pistons, rods and cranks, and even balanced complete assemblies are readily available from a wide range of engine parts suppliers. To fill this block, Bryce Mulvey of Dr J’s Performance started with a cast steel 9000-Series crankshaft from Scat. Bryce tells us, “For a hot street application, this Scat crank is very reliable; it is a great value for the money.” The Scat crank is linked to a set of Scat 2.123-inch journal 5.400-inch H-beam rods. Off-the-shelf Probe flat top stoker pistons complete the stroker conversion. The factory main caps were retained, but added clamping was provided by the use of a set of ARP main studs.

Let It Breathe

With more cubes on hand, the next area of focus would be improving the airflow. Here, the production heads were shelved in favor of a set of lightweight aftermarket aluminum castings. A used set of AFR 165cc castings were the starting point, but these were heavily ported to achieve better than 300 cfm of airflow. Bryce relates, “AFR definitely has higher capacity heads that would have been a better place to start, but we already had these heads, and porting is what we do. We ended up taking a huge amount of material out of them to get them where I wanted, but the final flow level will support quite a bit of power.” The cylinder heads feature Manley 2.055/1.600-inch valves, and were assembled with Comp number 26094 springs with all new retainer and keeper hardware from Comp. The springs deliver 200/465 pounds operating load for use with a hydraulic roller cam.

Bryce went with a hydraulic roller for improved street durability, “The hydraulic roller takes all the worry out of wiping a flat tappet cam in street use, and it lets us run much more spring load reliably. Even with a moderate cam like the one in this engine, the lift is going to be way more than a factory flat tappet, and that takes more spring. Add in the cylinder heads that can use the lift, and the higher rpm, and you have a tough balancing job with a flat tappet between spring load and durability. The hydraulic roller lets us have both.” The Comp roller grind measures 239/242 degrees duration at 0.050 inch, while giving 0.584/0.577-inch lift via a set of 1.6:1 ratio Crane aluminum rockers. The cam was ground to a lobe-separation angle of 110 degrees and installed at 104.

On the cam selection, Bryce continues, “For all-out horsepower, this engine would have benefitted from more duration; something in the 250s will make 25 to 30 more horsepower at the top. Because this application is going to be primarily street driving, we pulled back the cam duration for a better idle and lower end torque. It is still big enough to make power and put the peak output in the 6,000-rpm area, which was the target here. The lobes are not very long in duration, but they are quick enough to offer a good amount of lift, and our heads will take advantage of any lift you can throw at them with more flow. You have to be careful here, though, because if you go too aggressive valvetrain control becomes an issue and you don’t want to beat up the valvetrain in a street engine.”

Completing the induction is an Edelbrock Performer RPM Air Gap topped with a Dr J’s–built Holley 950. Bryce detailed the selection, “Like with the cam, the manifold selection was influenced by the intended application. No doubt about it, a ported single plane will make more top end power, but the longer runner two plane will have noticeably more pull through the bottom and midrange. For a street engine, the two plane is going to be the better choice. On the other hand, the carb might seem big, but we custom built this one and dialed it in for the engine combo. The two plane really only draws from one side of the carb at a time because of the divided plenum, and the added capacity is going to show an advantage in power. The way it is set up, it is a very drivable induction system.”

Vital Specifications: 347 Ford Windsor
Builder: Dr J’s Performance
Bore 4.030 inches
Stroke 3.250 inches
CID 347 ci
Block Ford Factory 8.200 deck
Compression Ratio 10.75:1 with flat tops
Engine Fasteners ARP
Crankshaft Scat 9000 series
Camshaft Comp custom hydraulic roller
Timing Chain Comp Tru-Roller
Lifters Comp
Pushrods Manley 5/16 diameter 0.080 wall
Spring Comp Cams 26094
Installed Height 1.850 inches
Spring Load (pounds) 200/465 pounds Closed/Open
Retainer Comp
Keeper Comp
Intake Duration 239 degrees at 0.050
Intake Lift 0.584-inch gross
Exhaust Duration 242 degrees at 0.050
Exhaust Lift 0.577-inch gross
Rocker Crane 1.6:1
Lobe Separation 110 degrees
Installed Centerline 104 degrees
Top Ring Total Seal Classic 1/16
Top Ring Gap 0.017
Second Ring Total Seal Classic 1/16
Second Ring Gap 0.028 inch
Oil Ring Total Seal 3/16 standard tension
Piston Probe Forged
Main Fasteners ARP
Rods Scat 2.123 journal, 5.400 inches
Bearings Clevite
Main Bearing Clearance 0.003
Rod Bearing Clearance 0.003
Cylinder Head AFR 165 Ported By Dr J’s Performance
Peak Intake Flow 301 CFM
Peak Exhaust Flow 235 CFM
Intake valve diameter Manley 2.055 inches
Exhaust valve diameter Manley 1.60 inches
Cylinder Head Gaskets Fel-Pro MLS 0.050-Inch compressed
Piston Quench Clearance 0.038
Intake Manifold Edelbrock Performer RPM
Carburetor DR J’s Holley 950
Header Falcon Chassis headers 1 5⁄8 primary, 3-inch collector
Ignition Mallory
Distributor Mallory
Spark Plug Wires Moroso
Damper PowerBond
Water Pump Procomp Electronics
Oil Pan Canton
Oil Pump Melling HV

To the Test

The engine was set up on Dr J’s Superflow Powermark engine dyno using the set of Ford Falcon chassis headers that will be run in the vehicle. The ignition system was from Mallory, firing the plugs through a set of Moroso wires. Other details included a Powerbond damper and Proform Electronics water pump up front and standard pump gas in the dyno’s fuel system. Fired for break-in, the engine seemed to hit the mark, with a noticeable performance rumble, but very good manners showing idle vacuum hovering at around the 10-in-hg mark and an engine idle speed of 900 rpm. After the adjustment basics, it was time to pull the handle for the numbers. There was nothing to dislike about the results, with the engine pulling flawlessly to 6,500 rpm, while delivering stout output.

As expected, the torque came on strong from the bottom of the rpm range and surged in the midrange to a peak of 458 lb-ft at 46 to 4,700 rpm. Power peaked at 5,900 rpm, showing a stout 485 hp from the 347 cubes. This was pretty much right on target for peak power rpm, but the engine really lingered around that peak for quite a broad range. Output was more than 475 hp from 56 to 6,500 rpm, in kind of a plateau of strength. It’s performance like that which makes the little 347 stroker Windsor a favorite.

Dyno Results
347 Windsor Ford Stroker
Superflow/DTS Engine Dyno
3,000 386 221
3,100 396 235
3,200 404 247
3,300 413 261
3,400 422 273
3,500 430 289
3,600 438 301
3,700 444 313
3,800 447 324
3,900 450 335
4,000 453 346
4,100 454 355
4,200 455 364
4,300 455 373
4,400 456 382
4,500 457 395
4,600 458 405
4,700 458 415
4,800 456 422
4,900 456 433
5,000 455 439
5,100 454 445
5,200 451 458
5,300 448 460
5,400 445 462
5,500 441 468
5,600 435 473
5,700 431 478
5,800 427 482
5,900 423 485
6,000 413 483
6,100 406 483
6,200 400 481
6,300 393 478
6,400 385 477
6,500 377 475

Air Flow Research
28611 W. Industry Drive
CA  91355
Canton Racing Products
232 Branford Road
North Branford
CT  06471
Crane Cams
1830 Holsonback Drive
Daytona Beach
FL  32117
Holley Performance Products
1801 Russellville Rd.
Bowling Green
KY  42101
925 Tower Ave.
WI  54880
Probe Industries
2555 West 237th Street
CA  90505
Comp Cams
3406 Democrat Road
TN  38118
Fel-Pro Federal Mogul Corp.
Manley Performance Products
1960 Swarthmore Avenue
NJ  08701
Scat Crankshafts
1400 Kingsdale Ave.
Redondo Beach
CA  90278
VP Racing Fuels
P.O. Box 47878
San Antonio
TX  78265
Mallory Ignition
10601 Memphis Ave. #12
OH  44144
Melling Engine Parts
2620 Saradan Dr
PO Box 1188
MI  49204
Total Seal
Moroso Performance Products
80 Carter Drive
CT  06437
2700 California St
CA  90503
Dr. J's Performance
436 S Montgomery Street
CA  92868
Procomp Electronics
605 S. Milliken Avenue
Unit A
CA  91761