my 355” (340 block) is no power house but it does runs 9.70 at 137 at 2700lbs with no signs of any problems. Not sure what it makes for power but it runs good and this is the typical 340/360 build. Low 10’s mid 9’s is very common with stock blocks.
I have thought about bumping up the compression and adding a roller cam to run 9.40’s but I’m happy for now.
Anything faster I think it’s race block territory.
