foo

I need help on how to find out what block I have and I also need to get it bored out and machined due to rust in the cylinders. I was wondering what all to bore it to and so on?

cutlassefi

A little more info would be helpful, intentions, location etc.

import extermination

casting numbers are located on the ledge above the water pump. or look at the number beside spark plug #1

507OLDS

396021F is the casting number for ALL 455 blocks.They also had 396021Fa blocks from 73-76.

foo

Im wondering what the original specs of the block and was wondering when I do get it cleaned up and bored if there is a certain measurement. Im only trying to restore it not make it into some monster machine yet

joe_padavano

The Chassis Service Manual has all the critical dimensions and tolerances for your engine (and everything else on the car). A 455 block can be bored 0.060" over easily, though you only want to go the minimum necessary to clean up the cylinders.

red&blue442

What is the difference between an F and an Fa block, other than the years?

foo

Any idea where I could find one of these manuals?

MDchanic

You could always start here...

- Eric

507OLDS

The earlier 68-72 blocks have thicker cylinder walls,and can be bored easily to +0.060,and still have good thickness,or could be bored even more.The later smogger blocks,as I call them,don't have as much thickness,and I would try to stay at +0.030 with those.A +0.060 overbore on those will generally make them thin,which will result in slightly hotter running temps.
A thicker cylinder wall will also aid in ring sealing.