The legendary 427 side oiler was at the time perhaps the best engine of it's time!! That was the engine that powered the GT-40's to wins at LeMans. It was VERY competitive in NASCAR. The top and center oiler 427's have good oiling, but not AS GOOD as the side oiler. At SUSTAINED rpms in excess of 6000 rpm or so (and they often turned 7000) these engines would experience crankshaft
oil starvation. But SUSTAINED high rpm is a problem for ANY engine, then and now! Hour after hour at 6000 rpm, how would a MODERN engine hold up to that you think? Like LeMans, for 24 hours!
No modern engine built today would go to LeMans without MAJOR re-working of the oiling system and many other components. It could NOT survive 6000 rpm for hours on end. Yet the 427 side oiler as delivered "back in the day" was ready for LeMans right out of the box!
To provide a more reliable bottom end the "side oiler" came out in 1965. The difference is that
oil goes FIRST to the crank shaft journals and secondarily to the camshaft and upper end. I think it's mis-leading to say this is was an "oiling problem", it is an oiling enhancement due to the EXTREME race conditions.
I recently had my High Rise heads worked on at a local machine shop that SPECIALIZES in heads. The guy was blown away at the size of the intake ports, he called some racing friends to come over and check out the heads. THEY were impressed as well. These are 1964 heads on a 1968 side oiler block. Even TODAY this is a very impressive combination. Ports as large as these are very rare indeed, then and now, on ANY engine!
Side oilers were used in only a very FEW Ford cars, usually special order and built to race. The engines are scarce, then and now, there sole purpose in life was to win races, and they did that very well indeed!
But Ford cranked out THOUSANDS of "427's" many of which were used in industrial applications. Generators, air compressors, boats. These "standard issue" top or center oilers were quite common, heck they were everywhere! For the most part they were far from "race ready". Low compression and low rpm engines that would go and go and go, just not very fast! For this reason many people assume that the Ford 427 was an "also ran" at best. These engine had tremendous "potential" but typically came with small valves and mild camshafts and produced by the thousands in that configuration.
The "side oiler" is a different animal all together, not at all like the industrial versions. IT IS the "holy grail" of 427's, rare then and now! This basic engine later became the feared and quickly banned SOHC motor. SO powerful no other engine could begin to compete with it. Recently it was ONCE AGAIN banned from drag racing. Even TODAY that engine is STILL feared! It had more horse power than the also legendary Hemi of it's time.
Due to their thin wall, light wieght casting they were difficult at best to "get right" at the factory. Many became simply industrial blocks. Because of the unique methods used to cast and prep them they were VERY VERY expensive to produce. The 428 basically replaced them at a fraction of the cost. Thats why Shelby started using the 428 instead of the 427. They LOOKED the same, but were far from it internally.
..and the top loaders are about the strongest trans out there. Certainly WERE the strongest "back in the day". Not to mention the legendary 9" Ford rear end which first came out in 1959. THAT same 9" rear end design is what is used by 99% of the the NASCAR teams today, and a BUNCH of serious drag racers! What other design from 1959 could be found at NASCAR today? Ford rocks!