302 and 351w, are they same block famly or am i going to have to change all the font brackets and pulleys if i swap 351 for 302

 

They are the same family and mostly it will bolt up. If you are putting a late block in an early chassis you won't have a drilled and tapped hole for clutch linkage.

The timing cover and water pump will fit, but the bolt holes in the head are in a different location due to the increased deck height.

If you are not changing a complete engine, you will have to come up with a different intake manifold and distributor.

If you are not putting it in a truck chassis you might have hood clearance issues and although it is only a slight difference, you might have exhaust pipe fit up issues.

Hope this helps.