[SFfiredog]

Cliff,
Tunnel port heads love cubic inches. The bigger the better if you are looking for low end torque. For tunnel ports that are under 450 ci (or engines with bore sizes smaller than 4.25) I like to reduce the valve sizes, 1.675" exhaust and 2.19" intake. This helps reduce valve shrouding and actually increases flow and low speed velosity with the smaller valves. The tunnel port already has machined combustion chambers so there really isn't much to be done there although it would be better if the chambers were smaller on 427ci to 450ci engines. A flat top or inverse dome piston will give you better combustion and help stave off detonation for the same given compression ratio. Leave the intake ports alone but some exhaust port work is desireable but make sure whoever does it is familiar with FE heads. I've seen plenty screwed up by Chevy head porters with the best intentions! On bigger (475ci and up) I run 2.20" intake and 1.71 exhaust valves. I'm finishing up a 483ci tunnel port at this time and will report the dyno results. as far as cams are concerned, the one you have doesn't sound bad although I would like to know what the duration is a .050" lift. You don't need a big intake/exhaust split in lift and duration on tunnel ports. I would run a mechanical flat tappet with high 240 to low 250 degree at .050" lift and in the .590s" lift. If you are looking for more low end torque go with duration in the low to mid 240s at .050"
HTH,
Mike