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?

 

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

 

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

 

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

 

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

 

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.

 

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

 

Any idea where I could find one of these manuals?

 

You could always start here...

- Eric

 

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.