340 build advice needed

I get about the same Static CR: right around 10.4:1. With the larger cam, the DCR is going to be fine as is: 7.8 at and ICL of 110 and 8.0 at an ICL of 106. I would set up the latter, just to keep a bit better low RPM torque. (And I just now read the above post so looks like we are at the same spot.)

It will be fine; I've run 10.3 and a higher DCR on pump gas with iron heads. Just sneak up on the total ignition advance slowly and don't worry if you can't get total advance up to the numbers some do with lower compression engines.