Budget cylinder heads for a 318

300/325 for a 318LA is no small thing. This is more than a cam swap.
If your cylinder pressure doesn't keep up, the power will all be in the rpm....... leaving the bottom end very soft. Then you will need a hi-stall and probably 4.xx series gears to drive it at normal rpms.
Forget putting a manual trans behind a combo like that.
And forget running it at anything but close to sealevel. The higher you go, the weaker the pressure gets. Pressure is power, especially at lower rpms.
To make your numbers; besides the right cam and pressure, you will need heads, headers, a free flowing exhaust, the usual bolt-ons and probably fresh air to the carb.

IMO
you'd be better off and bucks ahead , if you lowered your power target, or just stuffed a 360 into it. It doesn't take much for a 360 to crank out 300/325 .
But if yur stuck on 318, then, a 5.2Magnum already has a 9/1 compression ratio, better heads, and was rated 230 NET horsepower ..... which might be closer to 270 on a dyno. With a small cam, and the usual bolt-ons, she'll be crowding your target and be ready for fun.