The idea of boring a 307 .125" over has been around for along time. 30 years ago, the failure rate was about 1 in 10. Today you would have to take into account water jacket corrosion and such. A sonic check would be the only way to tell for sure. With 4" blocks so easy to get..... Don't know if I would go there or not.
Another thing to think on, the 302 pistons all had a tall dome. .350" was average. 11-1 with a 64cc head. Add another 1/4 to the stroke and compression will go higher. If the pistons are TRWs they will have a thick top and can be milled to drop the compression a bit. I think TRW is the only ones still making a 302 piston off shelf.
You can still use the 307 block if you have to. A 283 has the same pin height as the 302. A .030 or .060 over 283 piston will work with the 5.565" 400 rod and a 3.25" 307 crank. Will leave you about .035" in the hole. At .060 over you should get about 316 cubic inches. Almost the 327 you are talking now.
If you want more torque, a 305/350 crank can be added. Use the 307 piston and 400 rod. You can get a 339 inch high torque set up that a set of vortec heads will accent nicely. Dan