428 vs 427

[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

[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 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