318/360 Crank/347 running on Dyno

I think that 360 Offy is a good manifold for torque on a 318.

Like you said, it's choking, though. I think you could even benefit from an LD4B or a Weiand Stealth without having to port match on the 302's. I'd be curious to see what that did. The 360 manifold is a good idea, but it's just a little on the low volume side, like the SP2P. Sort of like a step between the SP and LD series from Edelbrock.

The 302 heads, IMO, are better suited on a 318/ 340 crank 318. You are right on target with the Magnum heads and intake combo bumping it up.

One of the things that the 347/ 318:360 crank engine isn't, is a 318. It has closer needs to a 340 in head CFM, but it will not behave like a 340 in RPM.