Displacement

[K.F.M.]

I have been told an Olds 403 engine can be bored out to 421  I think this
is beyond its limit . Could somebody please confirm eitherway
Thanks

[wayne petty]

but why when you can get a 455 block....


if you really intend of going there    you have to have the block measured with an ultrasonic device..  that is done on almost every race motor... move the little paddle over the every cyliner wall from top to bottom while looking at the display.. most of the better race machines shops will have one...

if there is something special about 403 motors i might be wrong.

hmm people take a 302 to 347 by boring and stroking...

a 428 crank in a 427 block makes like 450+ inches out of an fe...


sorry i don't have an exact answer for you... anybody else...

[Harry]

What is the bore on a 403?
How much would you have to bore it to make 455?
1/16" ?  .0625?