HELP! small block to big block swap

[Mr. GMC]

I have an 86 shortbed C10 I am about to put a 489 cu in big block in; the truck had a 350 in it; what mounts have to be changed? block mounts?, frame mounts?, frame mount towers? Any or all? This is my first big block swap so any other tips related are much appreciated. Also, this is going to be a 700 horse motor, so should I use solid mounts, poly mounts? I have heard that high horsepower big block chevys have been known to spin the main bearing where the motor mount is because of block/main web deflection. What about a front plate? Thanks again for any tips or advice.