what solid cam is equivalent to a hyd 268 ?

Here's some Desktop Dyno numbers for the different cams. All would work on the street but with more horsepower comes more rpm and more torque at lower rpm looses horsepower. It all depends on what you want and the rest of your combination. Now that you are rebuilding the 273 what pistons are you going to use? (Compression) Are you porting the heads? A bigger cam will probably need a steeper gear to make it work better (and rev faster) I see you have 3:55's. Make sure you set up the distributor curve. The best thing I did to my 273.

E4 HP 278 @ 5000
TQ 328 @ 3500

128F HP 286 @ 5500
TQ 326 @ 4000

132F HP 306 @ 5500
TQ 324 @ 4000

TQ30M HP 307 @ 5500
TQ 324 @ 4000