Since most of my antique racing was done with flathead Fords, I have a very limited amount of experience with 261's. One of our competitors back in the early 1960's in "Hobby Stock" class racing which was limited to flatheads and inline sixes gave us a little bit of a run for the money with a 261 (which he called a "Canadian Pontiac") but once we got the rules changed to allow 4" stroke Mercury crankshafts in Ford coupe bodies and almost caught up displacement-wise, (252 cubic inches instead of 239) he couldn't stay within half a lap of us.

Machining for the mains is simply a matter of cutting a slot at the parting line instead of drilling a dimple at the top center of the main bore, so the casting core could have gone either way, I suppose.
Jerry


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