Does your 350 have a dished piston? If so the compression ratio is very very low with 487 heads. The chamber volume on 487 heads can be as big as 80cc. That, combined with a dished piston and .040" composite gasket= very very low compression. potentially as low as 7.50:1
If that is what you have now, you need a head swap.
Don't even think about moving the summit cam to another block. its a $78 cam with new lifters. If you want to re-cam, get a new one.
Your motor has mediocre performance cause you have very low compression, low flow, stock smogger heads.
A cheap, effective, low budget solution is to fully home port and modify a set of high compression #416 305HO heads and swap them onto your 350 block. If your 350 has a dished piston, use a thin felpro #1094 steel shim head gasket.
Modify the 305HO heads for a 1.6:1 intake rocker arm (lengthen push rod guide slot, drill and roll pin stud bosses) and fully port them. Rob the 1.94" intake valves out of your 487's and have a new valve job done on the 416's after all the porting is done (by you).
Your new compression ratio will be higher so you can now use a larger cam and still have a good bottom end pull and efficient cruising.
Use Comp cams #12-208-2 cam and get 8 1.6 rockers for the intakes.
specs with split rocker ratio
265°-269° adv 211°-221°@.050" .471"in -.465"ex lift 110° LSA
The increased compression ratio + improved cylinder head port airflow+ new camshaft will add a significant amount of real usable torque and power.
Air flow, cam timing, compression, it all has to work together.
A moderate jump in rear gear ratio will help seat of the pants performance as well. If you have a short 26" rear tire a 3.42 is good. if you have a tall 28" tire use 3.73's