so im wondering if theres any way to tell the dif between a 305 and a 350 just by looking at it...the intake mani isnt stock on the motor..so no part number there..any help would be great...

Look in the back of the block on the drivers side, in front of the transmission. You may have to get a little mirror to see it. On the newer blocks it will say 5.0 or 5.7 but if it doesnt, look at the casting number and just type it in on Google.com. you will get plenty of pages on what block you have.