1968 firebird 455 engine swap

i know this question has been asked and is probably somewhere in these but I need the info a.s.a.p. I just bought a pontiac 455 for my 68 firebird wich had a 350 before, i need to know what fabrication if any i need to do and what mods I need to do to drop the engine in like the proper engine mounts i need to buy wich flywheel should i get, i have a 350 currently. Where to get the proper alternator mounts and power steering mounts. please email with any info at oldirtysmolik21@yahoo.com. thanks  

I installed a 455 in my 68 Firebird, and it was a bolt in swap for the most part because I had a '70 block, which was manufactured with five threaded engine mount holes down the side of the block(made that way so they could be installed in all Pontiac car lines).  If you have one of these, you just have to match up the holes to use with the ones your original engine used.  Mine came without pulleys, so I did have to get pulleys from a junkyard, as I think the '69 and later water pump/front cover are slightly longer than the '68 earlier ones.  I reused my existing '68 alternator and power steering mount hardware without problem once I had the right pulleys.  If your 455 came with pulleys but no alt/PS mounts, you can probably reuse the one's from your 350.

I understand the 455 five hole block was standard from maybe '70 to about '74, although in some of the later ones not all the holes may be threaded.  If your 455 block does not have matching holes for your 350, there are adapter mounts available from some of the Pontiac specialty suppliers to do the job.  

If you are new to Pontiac engine details, the reason this is so easy is that there is no significant exterior difference between a Pontiac 350, 400, 428, or 455 block, (except the motor mount holes) which makes the swap so easy.  

The flywheel/flexplate center hole size must match the flange on the crankshaft, and there are two sizes I think, so you may need to get a later flywheel to match your crank, as your '68 flywheel may not match the later 455 pattern.  I don't know the year or size break on this, so measure first, you might be lucky and be able to use what you have after all.