if you go to the 351w you will need new headers.
I stroked mine to 354 ( that's a 347 with .070" more stroke. I got a deal on the Eagle forged kit.) and I'm making 402 rwhp and 416 rwtq.
I can hold my own with my big block buddies.
stroke it

buy your heads and cam from Keith Craft, that's where the hp is.
Dwight