[MOTORHEAD]

Thanks for the info guys. The heads really only need port matching, and it doesn't look as daunting this morning as it did last night !
Rick: I'm not using the felpro gaskets, but special 1/8" thick and larger around the ports.
They are available through Barry Robotnik @ Survival Motorsports. The extra thickness makes for a better fit with the milled intake and heads.
Undy: That sounds reasonable to me.
Hans: Looks like a good reference . I'll get one regardless.
W.: The intake ports are larger than the out-of-box E'brocks by the dimensions stated in my original post, but far from hi-riser dimensions. It had to have been mated to ported E'brock or FE iron heads, the only 2 options for FE heads that I'm aware of.
Carmine:I tried for a new manifold originally, but could not find one . This one came with the carbs, so I went down that road. I may change it out if it doesn't work out.