Thread: 305 vs 307 (whats the main difference?)

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Originally posted by techinspector1
How about a little firewall massage with a BFH?

What is that Tech ? A Ball Feen Hammer?

nope, a big ******* hammer

Im in the same boat as Mr. Nova. I have a 1968 307, and i would like t bore it to 4.00. I have seen kits on the internet, but the local machine shop said you cant bore it out that big. I have heard conflicting stories, but i really want a 327. I like the short stroke for the revs and im not to concerned with making alot of horsepower or stroking.

For any of You that want to keep that original 307 block but want a 327 or a 350, Yet you have allowed some here to scare you to thinking it can't be done, There is a simple solution.
Have the block sonic tested. This tells you or your machinist what the thickness of each cylinder wall is. Then your machinist will know for sure if each cylinder wall will handle a 4 inch bore.There could be a rare case that you might find a 307 block that 6 or 7 cylinders would check fine and 1 or 2 might be too thin. If thats the case do not go there.I would much rather have a 350 block to start with but it can be done and it can be done safely. The main problem here is that 5 years down the road it can not be bored again if it needs to be rebuilt. The only thing you could do then is re-ring it.