I'm planning a build with similar objectives, here's what the plan is so far:
- mildly ported Magnum heads
- Hughes HEH2328AL or HEH1928AL cam, still haven't decided yet
- TTI headers
- Edelbrock RPM Air-Gap intake
- KB hypereutectic pistons, sized for ~10.5:1 compression
- Edelbrock Thunder AVS 650 cfm carb
I know 10.5:1 compression is rather high for an iron-headed pump-gas engine, but with some combustion chamber mods (edge-radiusing) I should get phenomenal combustion speed and detonation resistance, allowing me to run less timing advance and lower-octane gas (hopefully as low as 87-octane!!!). All these things, along with an OD 4-speed manual should hopefully get me at least in the mid-20's highway gas mileage.