i have a 350 and im having it bord 30 over but im keeping the 350 crank in it. Now what would you guys think the engine size would be?????  

for every .30 its usually around 6 cubi inches. Most people call .30 over 350's 355's  

If its a Chevy 350,yep,u gonna hava 355cid.FYI,if its a 4bolt main,have the machinist pressure test the block,and sonic test it if their equiped to.Those 4bolt blocks like 2 crack in the bottom between the waterjackets and oilgalleys for the mains(along the sides of the 6 outer main bolts do to thin walls).Ive seen so many crack I wont even chance a 4bolt block.I use a 2bolt,spend the money to install splayed maincaps if for racing.