347 vs. 351 in 69 Mustang

The 351w is a real favorite of mine, I've beaten on a few them and they have not disappointed or let me down. If I'm not mistaken the Chevy LS cylinder head owes a good bit of it's design to the Ford Windsor head.
I'm in something of a similar situation to the op, my Bronco is pushing 180k miles, still running good, but I know it's probably getting a bit tired. It was born with a 302, and I have another complete 302 under my bench, but I would like a little more grunt. I have also been thinking about dropping in a Coyote 5.0 and a 6 speed auto trans, but not sure if I want to go that far with it. I'm not looking for anything wild, it's my daily driver and I only put 50 to 60 miles a week typically. Reliability is the most important factor.