Actually a lot could have been done to make bigger numbers if that was the objective - I had a modified M-1 intake to try but no time, and yes the headers were small. The reason for that though was the customer was going to run full exhaust and 2 3/4 collectors was closer to what the in car senario would be.

Good info on the differences between the RHS and the EQ. The RHS is wider at the pushrod crossection of the intake port pair. That means the intake port window at the pushrod pinch can be larger on the RHS. I was trying to get RHS to cast a version of this head with machined pushrod holes which would open up the option of machining them wider for use with offset intake rockers. But it's like Ross Perot said of GM, "It is easier to get an elephant to tap dance than get a big company to make a change."