428 vs 427

[somedayaurora]

Anyone know the performance difference between a MKIII with a 427 and one outfitted with the 428 ?
thanks
sdr

[blykins]

Way too many variables there....

Each engine can be made to produce 350-600+ hp.

[somedayaurora]

I was wondering stock from carol .
sdr

[Dwight]

the 427 is a large bore short stroke motor (4.23" bore x 3.78" stroke) made to produce horsepower at high rpms. By 1965 Ford had a 427 motor that could run 7500 rpms for 24 hours.
The 428 (4.13" bore x 3.98" stroke) is a low rpm torque motor for the street.

Both can make the same horsepower.
Coach Mike has a Keith Craft 428 stroked to 461 making 601 hp & 619 tq at the flywheel.
Mike Lainhart has a '65 427 s.o. that Keith Craft stroked to 487 that makes 619 hp & 632 tq at the flywheel.

One is 9:0 to 1 and the other is 9:5 to 1 compression.
Both are very street-able and great Cobra motors. Push the gas pedal to the floor and hang on!
With the heads and cams available today you can have a great street motor with a lot of hp. Just tell your motor builder what you want.
Dwight

[Tim Brewer]

Just two different engines. To me, one is just as good as the other. But most people will say the 427 will have more value to it.

[CobraEd]

Same engine, . . block,heads, etc. Just bore & stroke difference. Not a big deal in normal street driving.



.

[undy]

Originally Posted by CobraEd

Same engine, . . block,heads, etc. Just bore & stroke difference. Not a big deal in normal street driving.



.

Dunno where you get that?? Block is ENTIRELY different. Head castings were different too. It was WAY more than bore 'n stroke...

[blykins]

Originally Posted by somedayaurora

I was wondering stock from carol .
sdr

The 428's were rated for about 335hp. If you dyno a near factory 428 today, you'll see about 375-385hp. The 427's were rated for 425 hp, but I'd say they were a little under-rated as well.

[somedayaurora]

so 428 less power more torque and a little less temperamental , 427 more hp at the top end . That about right guys ? remember stock 60 engine . Oh any weight difference?
sdr

[Dwight]

buy the book
HIGH PERFORMANCE FORD ENGINE PARTS INTERCHANGE by George Reid

no real weight different.

Dwight

[olddog]

One of the guys on club cobra who owns an original, sent me some PDF files that were copies of the original Shelby brochures.

I am pasting the 428:
428 CID Speclal Police Interceptor Ing'inc r'riih rnod'fii caticns
by Shel by Ameri can.
l^lat,er cooled, crst il"oir block witit 5 ma'in bear-ings
Sore 4.13 Siroke 3.9t] Dispjacetnent q28 cubic irrches-70l4cc
Compression ratio 10.0:l Carburet'ion 1-4V Ford
Horse power 390 @ 5200 RPM Torque 475 f t 1bs. @ 3700 RPM
tlec^urical system 12V battery, alternator
Va'l ve train - Pushrod, 0.1'1.V., l'lechanical l i f t e r s
Mi leage 9-12 MP0 Prenrium on'ly, reconmended

pasting the 427 street version:
Water-cooleVd -8,w ith cast iron block,5 main
bea ri ngs
Bore & stroke . .4.24 x 3.78 in, 107 x 96 mm
Displacement . . . . .427 cu in, 6998 cc
Compressiorna t i o . . . . . . . 1 0 . 4 t o o n e
Carburetion . .Two 4-bbl Holley
Valveg ear Pushrod-OHV
Horsepower (SAE) . . .425 bhp @ 6000 rpm
Torque . . 480ft-lbs@ 3700 rpm
Electrical system. . . 12-volt battery, alternator
Fuelrecommende. .d . . P r e m i u m o n l y
Mileage . . . . 9 . I 2 m p g

Pasting the 427 Competition:
Water cooled V-8, with cast iron block, magnesium
intake manifold, alloy cylinder heads,
lightweighvt alvesa nd alloy water pump.
Bore & stroke . .4.24 x 3.7B in
Displacement 427 cu in
C o m p r e s s i o n r a t i o . . . 1 2 . 4 : 1
Horsepower. . . . . . . 4 8 0 @ 6500 rpm
Torque 510 ft-lbs @ 3700 rpm
Carburetion .4 V Holley
w/center pivot float bowls

[olddog]

The 428 is a center oiler design. If memory serves the oil goes to the cam first and then down to the mains. The 427 side oiler put oil to the mains first and then up to the cam. As cast from the factory (today people improve the FE oiling) the 428 cannot turn much north of 5500 rpm in a long race without loosing bearings. The 427 side oiler could turn close to 7000 rpm. The racers of those day were turning them 7500 - 8000 rpm but I suspect those were modified.

The 428 smaller bore limits the valve diameter, and has smaller valves than the 427. It cannot breath as well as the 427, as a result. Therefore as cast, the 428 cannot make as much power.

Blykins is correct that Ford advertised 335 Hp for the 428. Shelby advertised 390 hp and noted that he had modified the engine.

I hope this is the information you were looking for.

[rms427]

My car originally had a 428. It was rated by Shelby at 390 HP. It had the same AA mechanical cam as the 425 HP 427 and an aluminum intake manifold, Ford 4 bbl carb, low riser 427 heads and 10.1 compression. I replaced the carb with a 780 3310 Holley and added Mallory dual point distributor and side exhaust. Running Dunlop rain road race tires the car ran 12.40 at 112 MPH in the quarter back in 1970 at Lyons Drag Strip (sea level). I shifted at 5800 rpm and sometimes ran through in 3rd gear at 6000 rpm. "Stock" SC Cobras ran 12.20 in magazine tests with race tires.

I'm now running a sideoiler 427, medium riser heads with a higher lift mechanical cam and 9.5 compression. It doesn't feel any quicker than the 428. The 428 got 15 mpg and the 427 gets 10-12. Since I don't have a roll bar I cannot run at the drags anymore so I don't know how quick the 427 is. In the early 70's I didn't need a roll bar. Most likely it's a bit quicker than the 428 but not by much.

[saltshaker]

Have any of the engine builders built both a 427 and a 428 with the same comperssion,heads/ valves, cam, intake and carb and dyno them for a comparison?
Jon

[KevinW]

If its any interest, my 428 :

72 block
roller rockers
mild cam (my builder wanted a hotter cam, i talked him down) with all the low end torque piling in early
edelbrock heads and manifold
street avenger carb
Accel dizzy and 6AL box

dynoed
(ie not in the car) making 486 ft lb torque and 491 HP near the peak of the curve, 465 ft lb @ 3000rpm.

If i could have stretched to the S/O I would have, just for originality reasons, but I wouldnt have specced the engine much different. Im not going racing, but i will visit the Nurburgring and a few track days. But i mainly want my engine to stay in one piece when i drive it, and i want a nice smooth idle and a quick pick up.

[What'saCobra?]

There is simply no way even a factory 427 would last 24 hrs using 7000 rpm shift points in 1965 or much later.

The old large FORD 427 rod ends turned too high a surface speed above 6500 rpm and "sheared" the oil film. This wasn't popularly discovered until the mid-seventies and even today plenty of folks don't know it.

The center-oiling gallery was an half-failed well-meaning attempt to solve the wrong problem in the day. It helped a little, but 6400-6500 was still max on a longer race. Read how Guerny had to run slow at LeMans to keep AJ Foyt from breaking the engine.

Even today, you must revise the big end rods down to Chevy BB diameters from FORD's factory dia.

Only with the smaller BBC diameters will today's "hot" 427 FE's, with Cup Car steel and forged internals, aly heads w/big valves turn 7000 (or even a bit more!). Perhaps today with the much better specialty oils available, it might be possible to turn the larger rod/crank journal diameters up to 7000, but i would not try it regularly. It is too easy to get the correct (viz: smaller dia) rods and cranks today.

Unless a qualified engine builder revised the internals quite a bit, i would not believe a factory 428 would turn much above 5800-6000 in the day. Plenty of street torque, but nothing at the high end at all, perhaps 100+ short on power. Small valves, with little overlap on the cams, and smaller carbs restricted the breathing... mostly to protect the internal mud parts. Even the factory 427's didn't stay competitive until the tunnel-heads appeared.

Want to know a secret? Some of the FORD 427's were raced with Chrysler Hemi rods in the field, but NOT in the factory test cells. This was because a very few FORD racers knew the Hemi's were turning BIG rpms at the drags and they guessed/knew the success was because of the smaller rod/crank dia. This was a field mod that was kept very quiet from the factory until after the races were won. FORD (and the FIA) never acknowledged their existence. officially, except to a few of the sacrosanct.

[somedayaurora]

Originally Posted by olddog

The 428 is a center oiler design. If memory serves the oil goes to the cam first and then down to the mains. The 427 side oiler put oil to the mains first and then up to the cam. As cast from the factory (today people improve the FE oiling) the 428 cannot turn much north of 5500 rpm in a long race without loosing bearings. The 427 side oiler could turn close to 7000 rpm. The racers of those day were turning them 7500 - 8000 rpm but I suspect those were modified.

The 428 smaller bore limits the valve diameter, and has smaller valves than the 427. It cannot breath as well as the 427, as a result. Therefore as cast, the 428 cannot make as much power.

Blykins is correct that Ford advertised 335 Hp for the 428. Shelby advertised 390 hp and noted that he had modified the engine.

I hope this is the information you were looking for.

It is ! Thanks
SDR

[somedayaurora]

Originally Posted by rms427

My car originally had a 428. It was rated by Shelby at 390 HP. It had the same AA mechanical cam as the 425 HP 427 and an aluminum intake manifold, Ford 4 bbl carb, low riser 427 heads and 10.1 compression. I replaced the carb with a 780 3310 Holley and added Mallory dual point distributor and side exhaust. Running Dunlop rain road race tires the car ran 12.40 at 112 MPH in the quarter back in 1970 at Lyons Drag Strip (sea level). I shifted at 5800 rpm and sometimes ran through in 3rd gear at 6000 rpm. "Stock" SC Cobras ran 12.20 in magazine tests with race tires.

I'm now running a sideoiler 427, medium riser heads with a higher lift mechanical cam and 9.5 compression. It doesn't feel any quicker than the 428. The 428 got 15 mpg and the 427 gets 10-12. Since I don't have a roll bar I cannot run at the drags anymore so I don't know how quick the 427 is. In the early 70's I didn't need a roll bar. Most likely it's a bit quicker than the 428 but not by much.

Great info Thank you
sdr

[somedayaurora]

Originally Posted by What'saCobra?

There is simply no way even a factory 427 would last 24 hrs using 7000 rpm shift points in 1965 or much later.

The old large FORD 427 rod ends turned too high a surface speed above 6500 rpm and "sheared" the oil film. This wasn't popularly discovered until the mid-seventies and even today plenty of folks don't know it.

The center-oiling gallery was an half-failed well-meaning attempt to solve the wrong problem in the day. It helped a little, but 6400-6500 was still max on a longer race. Read how Guerny had to run slow at LeMans to keep AJ Foyt from breaking the engine.

Even today, you must revise the big end rods down to Chevy BB diameters from FORD's factory dia.

Only with the smaller BBC diameters will today's "hot" 427 FE's, with Cup Car steel and forged internals, aly heads w/big valves turn 7000 (or even a bit more!). Perhaps today with the much better specialty oils available, it might be possible to turn the larger rod/crank journal diameters up to 7000, but i would not try it regularly. It is too easy to get the correct (viz: smaller dia) rods and cranks today.

Unless a qualified engine builder revised the internals quite a bit, i would not believe a factory 428 would turn much above 5800-6000 in the day. Plenty of street torque, but nothing at the high end at all, perhaps 100+ short on power. Small valves, with little overlap on the cams, and smaller carbs restricted the breathing... mostly to protect the internal mud parts. Even the factory 427's didn't stay competitive until the tunnel-heads appeared.

Want to know a secret? Some of the FORD 427's were raced with Chrysler Hemi rods in the field, but NOT in the factory test cells. This was because a very few FORD racers knew the Hemi's were turning BIG rpms at the drags and they guessed/knew the success was because of the smaller rod/crank dia. This was a field mod that was kept very quiet from the factory until after the races were won. FORD (and the FIA) never acknowledged their existence. officially, except to a few of the sacrosanct.

WOW very cool Thanks
sdr

[somedayaurora]

Originally Posted by What'saCobra?

There is simply no way even a factory 427 would last 24 hrs using 7000 rpm shift points in 1965 or much later.

The old large FORD 427 rod ends turned too high a surface speed above 6500 rpm and "sheared" the oil film. This wasn't popularly discovered until the mid-seventies and even today plenty of folks don't know it.

The center-oiling gallery was an half-failed well-meaning attempt to solve the wrong problem in the day. It helped a little, but 6400-6500 was still max on a longer race. Read how Guerny had to run slow at LeMans to keep AJ Foyt from breaking the engine.

Even today, you must revise the big end rods down to Chevy BB diameters from FORD's factory dia.

Only with the smaller BBC diameters will today's "hot" 427 FE's, with Cup Car steel and forged internals, aly heads w/big valves turn 7000 (or even a bit more!). Perhaps today with the much better specialty oils available, it might be possible to turn the larger rod/crank journal diameters up to 7000, but i would not try it regularly. It is too easy to get the correct (viz: smaller dia) rods and cranks today.

Unless a qualified engine builder revised the internals quite a bit, i would not believe a factory 428 would turn much above 5800-6000 in the day. Plenty of street torque, but nothing at the high end at all, perhaps 100+ short on power. Small valves, with little overlap on the cams, and smaller carbs restricted the breathing... mostly to protect the internal mud parts. Even the factory 427's didn't stay competitive until the tunnel-heads appeared.

Want to know a secret? Some of the FORD 427's were raced with Chrysler Hemi rods in the field, but NOT in the factory test cells. This was because a very few FORD racers knew the Hemi's were turning BIG rpms at the drags and they guessed/knew the success was because of the smaller rod/crank dia. This was a field mod that was kept very quiet from the factory until after the races were won. FORD (and the FIA) never acknowledged their existence. officially, except to a few of the sacrosanct.

Wow very cool
thanks
sdr