Compression ratio too high for 91 octane?

Hey I need some advice, I’m looking at a 340 that’s been stroked out to a 410. Compression ratio is 11.8:1, I’m thinking that might be too high for me as id like an engine that will run 91 octane. I know it depends on a lot so here it the info the seller sent.


The 340 stroked to make 410cid, it's an eagle forged crank, eagle H beam rods, Mahle flat top pistons, the block has Milodon 23 degree splayed billet caps, comp solid lift cam, comp magnum adjustable shaft rockers, 2.08 stainless 11/32 stem int valves, 1.60 stainless 11/32 Ext valves, edel Brock Victor JR super int manifold, it should with a good quick fuel 750 cm carb and an msd ignition make very close to 500hp, it is 11.8:1 compression