Join Date: Feb 2002
Location: N.W. Washington
Re: ".035 to .045 quench will promote detonation"
On 400's the bores are siamesed, or connected at the side that joins the next cylinder in line. The 400 bore was larger and required this to fit in the smallblock package as it was. In cars that sat for hours idling etc., steam would build up at the point under the deck where the cylinders joined, creating steam pockets. They drilled holes at the two center cylinders from the block to the heads to complete the water jacket path when water was flowing at its slowest, i.e. idling. It was necessary to do because these motors went into vans, trucks and taxicabs, and the steam would build apparently at under 1800 rpm or so. In a car such as our Camaros the water flows well enough because they are driven, to never necessitate the holes. You always hear people say you need to drill them, but never an account of a time they personally didn't and had problems, it's just one of those things I guess....
Now I can tell you of incidences people decided to drill the holes and drilled them wrong........
1968 rs with an old school 354" SB2.2 pump gas motor.
Repetition does not transform a lie into a truth.
Franklin D. Roosevelt