428 vs 427

[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