Now your comparing an 8.5:1 to a 10:1 compression ratio and a 2bbl (304) ? To a 4bbl (290) !
The 4L only hit a max power of 195hp n 235tq so torque wise the 290 was hangin right with it, Now if ya installed the multipoint injection like the 4L had and the 290Lo stays right with it and the 290hipo surpasses the 4L.
Well there lots of other goodies that work on the 290's you make it a 295-297ci 12.5:1 duel quad 7,500rpm beast should one so choose to do so ;-)
Mike
You could up the compression on a 304 no problem, or even a 290. would scream, but 12.5:1 doesn't run super happy on pump gas without some work. a 7.5K RPM motor would be fun for the street, but you'd want a lot more down low power for 4x4ing. It's the same issues the 302 Z28's had. They wern't great off the line, but they screamed once you wound them out.
I think a 290-304 with 10.5:1 compression, a dual plane intake, 4bbl, decent lift cam and headers, and you could have a nice setup for an Eagle.