Welcome to CHR!

I'm sure Pat and Jerry will chime in soon as they are certainly our resident BBC experts and have built some of the best engines anywhere. I'm far from an expert on much of anything, but your question about longer rods did recall an article you may want to read - ISKY Racing Cams - Do It Right. Race with the Legend. Camshafts, Connecting Rods, Valve Springs, Lifters
See the Tech Tip 2005 on rod lengths.

As already mentioned, your compression ratio is a bit too high for comfortable street use especially with cast iron heads..

Hang around a bit - hope you find what you're looking for.

Regards,
Glenn