New 318 build, just need some input.

i think that cam is perfectly suitable for this build. it's basically a "plus one" from a 340 cam and the lift isn't that outrageous so i don't think you'll have any clearance issues. obviously it should *always* be checked, but you're not over .500 or using increased ratio rockers so you should be fine. i'd pull the trigger but check the return policy...

the heads are a big compromise here. i mean, you're not building something all that aggressive and there's a whole "use what i've got" mentality. that being said anything can benefit from a bowl blend/pocket port/gasket match. and in the case of the small port 302's might revisit consideration of intake (maybe something "small port" ie performer, LD4 or weiand 8007?) and possibly the cam.

the 650 DP is a fine choice. i personally would go a little more mellow with something like an AFB/AVS or a 750 vac 2ndary holley

change the heads and you change the entire nature of this build. that's the limiting factor.