Is there anything in common between a 403 and a 455 or 350 Olds motor? I saw an ad for a blown 403 I could get cheap. Is there anything that can be used on a 455? Is a 403 a big or small block? Thanks

 

The 403 is a small block. So whatever parts interchange between small and big blocks, such as brackets and such, will. But the heads, block, crank, etc. will not.

 

The 403 is a small block, by the definition of the deck height which corresponds to the 3.385" stroke used on all the similar small blocks.

Sorry, but a "blown" 403 isn't worth much, unless by "blown" you mean it has been fitted with a supercharger.

Parts common to a BBO
timing cover
oil pump
nuts & bolts
rocker covers
Distributor
Balancer
flexplate
oil filter adapter
starter
oil pan


Parts that may be worth extracting if the "blow" was not too bad:
403 XC rods