the earliest 283 blocks [57/8] can be bored .120 IF they don't have any corrosion in the water jacket, otherwise they can run too hot - the heavier 59 to 62 blocks can safely be bored to 4", but the 63-67 blocks shouldn't be bored more than 0.60, back to thinner walls

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics