The "race" bearings are made to withstand a much higher "load shock", and are therefore "tougher". They also may fail sooner due to metal fatigue. Usually best to use the bearings designed for the intended use. The 4040Ms have always "held up" fine. Actually, the 113M "race" bearings are a little less expensive than the 4040Ms. Both are "3/4 groove" for oiling. This is the ONLY way to "go". Avoid full-groove bearings for sure!
Lots of "confusion" surrounding what makes up a a "high volume" or "high pressure" oil pump for the Pontiac. Early engines used a 45 lb. pump with a 5/8" pickup tube. By mid-'66, Pontiac knew something had to be done to improve oiling. The 60 lb. "high volume" pump was developed. M54D is the Melling number. While it IS a higher pressure than the little pump, the 80 lb. "Ram Air IV" pump is the "high pressure" pump. M54F. Mail-order houses like Summit and Jeg's are partly to "blame" for the confusion, as they do NOT understand the "quirks" of the Pontiac, and apply "buzz words" from other engines in the descriptions.
In today's terms, the 60 lb. pump is the "high volume". It's also the only we use unless a high rev race engine is being built. THEN, the 80 lb. unit.
