if it's a 350 it will block cast numbers 305200,,, if its an 305 the block casting nu,bers will be 302600. an the exhast maniflod will have 7 bolt holes to bolt it to the head. How to fine the block casting number. Take a flash light, an in the back of the motor on the left side. where the trny bolts to the eng, there will be some numbers back there. You will fine one of these two numbers on the block. The emissions tag should have the eng size on it. But if the eng has been changed this is a good way to know the yr and eng size. If the number is different send it on here an I will look it up for u..