Chamfering the tops of the bore should help your cause in hopes to gain more flow. Your valves are large & the bores are smallish.

I use an extension that goes through the top of the intake port & use a socket to torque the nut

You could also use a torque adaptor & actually go through the intake port & torque it that way.
http://www.amazon.com/Stanley-Proto-J5118-Adapter-16-Inch/dp/B001HWEAEC

As long as the torque adaptor is 90 degrees to the torque wrench, you do not need to use a mathematical formula & compute the length of the torque adaptor..

At work I have had to make torque adaptors out of cutting up wrenches & add a 3/8 square drive adaptor just to reach certain areas on Gulfstream G5 BR710 engines.
It is just easier to have the torque adaptor 90 degrees & not worry about using the math formula every time you need to torque something.

I do not think this cyl head w/the 2.0" intake valves flows good, (not because of chamber shrouding the valves) but because we had to sink the valves to make the chambers bigger in order to lower the compression. IIRC, the compression ratio worked out to be 8.4:1.

I was not too worried @ the time about the flow because I had the Paxton supercharger forcing the air/fuel mixture into the engine.
Even though the cyl head probably does not flow too good, it was the fastest combination any my 250 ever ran. It ran low to mid 12's, but that is only because it was supercharged blowing through 3 48 MM Weber DCOE's.

I will most likely have my friend flow test my cylinder head, just to see where it is lacking & add the lumps & flow test again.

MBHD

12 port SDS EFI