Hey guys and gals.I have a stupid question.What`s the difference between a 305 and a 350? I keep hearing rhey both use the same block,only the heads and crank are different.Please help me out.

 

i dont know first hand, but i had a 305 block and i called a machine shop to see if i could have it bored out. they said you cant bure a 305 to 350 so i guess the block is kinda different

 

the actual block is the same, the bore size is different between a 305 and a 350. The calculation to find cubic displacement of an engine is [b]radius(or bore/2)^2 * pi * height(or stroke) = volume of a cylinder[b] * 8 cylinders

The bore of a 305 is around 3.72 and the stroke is 3.48. The stroke on a 350 and 305 are the same. I have heard of 305's being bore out to 308 but i don't know how much higher you can go than that.

You will hear the term "stroker" with engines, these will have either the same or a slightly larger bore but a much longer stroke than the 305 or 350, these are usually 327 and 383.

hope this helped

 

The 305 has a small bore as mentioned above. It cannot be safely bored out to a 350 without paper thin cyl walls. The 350 and 305 cranks are the same dimentions but the balance is slightly different. I've known many people to swap cranks in low rpm stock applications and be fine but I would rebalance if you are unsure or if you turn up the rpm. The 305 heads use smaller valves and smaller combustion chambers. You can bolt 305 heads on to a 350 to bump compression from the stock~8.5:1 to ~10:1 depending on your pistons. Bolting 350 heads onto a 305 puts the 'big' 1.94 intake valve really close to the cyl wall and drop compression into the basement.