Indeed panic . . .
I read the lack of mention of the so called steam holes in that article to mean that they simply didn't bother with them. A 235 head with a 235 gasket will seal these additional water jacket holes at the block; with a 261 gasket it will seal them at the head. But neither leaves the space above the combustion chamber high and dry. The primary water jacket hole is in the exact same spot on both heads - with the pressure from the water pump filling the entire space with coolant.
If we are arguing that the old school hat rod was under engineered when compared to modern standards - you will get no arguments here.
If we are arguing that GM had solid reasons for providing additional flow of coolant around the cylinder walls and up into the jacket above the combustion chamber on the 261 versus the 235 - again you'll get no arguments here.
In my mind the question is: Does a 261 tasked with making a '53 Vet go fast share the same cooling requirements as a 261 tasked with lugging timber up a hill on a hot summer day?
Racer's article suggests no (by omission).
If you disagree then the experiences of others indicate that one must drill with caution if one chooses to drill . . . But drilling is apparently a choice not a must . . .
regards,
stock49
