Building a 273

You have to notch the bores if you use 2.02 valves, but you don't have to on 1.88 valves. I don't know if you need to notch the bores for 1.92 valves in Magnum heads though. I had @replicaracer43 put 1.88 intake valves in my 302 heads going on my 273. I've had the heads bolted to the block with checker springs and the 1.88 valves clear plenty.