Double check my engine builder please 340 stroke

Way too much static compression.

I have a Scat stroker rotating kit, "63ccc" edelbrock heads (measured at 65+/-1cc) with the 274-S comp cam that at a glance looks close to what you have. I have 9.7:1 measured and CC'd and I run California 91 pump gas and on the edge of pinging on 90 deg days up steep grades. I have the icon 8-IC-745 +070 20.5 cc dish pistons

Way out to lunch with that compression, IMHO. Either he miscalculated the DCR or is bandaiding too much static compression with way too much cam.

But surprisingly the rest seems well thought out. And I believe his recommendation to go stroker is a great call for a hot fun street car you're building.