[tarmon8r]

331 has a better rod ratio that an 347 and supposedly will last longer than a 347 due to oil consumption. However, there is some speculation on that part. I have never done a 331 or 347. My question on stroking the 347 is what are you trying to do? Get a 351W? Then why not just put a 351W in it? But then the conversion comes into play. However, if you are building a stout motor, then the cost will be similar.

Then there is the whole stroker 351w combination, but that really comes down to dollars. Because cubic inches costs. Period!!! However, the 393, as you can see that I am partial to, is a good all around combination for a very economical price. As long as your not going to be hammering on it all the time.

They usually recommend late 60's early 70's blocks due to the increased iron content for greater strength and durability. However, the sportmans or R302 would be better upgrades over those. $$$$$$ however. 351 are just bigger and can handle more power due to there bigger journals and size overall. Goodluck with your endeavor. Keep us posted on what you end up deciding. Just trying to share some perspective. Peace.