Idk if you’ll see this, but this thread helped me start my build, ended up with 920 heads (pretty much identical closed chamber heads to 302s just ever so slightly smaller valves that don’t get shrouded and they move more air) and same mods as you just dif brands and I’m sure dif cam specs but the one thing I have done is use KB167 flat tops, they come up to almost 0 deck instead of sitting in the hole if you have 302 heads, if you’re running open chamber get KB399’s. They’re cast, and light and will hold up to whatever a normal person is throwing at a 318, theyre pop ups in OEM style that came in certain special 340’s just with a different bore, I did notch it ever so slightly where the spark plug it but I personally don’t have clearance issues with them although everyone here cursed me out for making a post asking if it was possible a couple days ago and figured I’d use the original heads instead of the 66/7 ones. Hub dyno came to 352HP 386lb/ft on the graph printout from after I finished it I just wanted to know because it was way rowdier than I thought it would be I guess the high compression plus a quench pad that’s helps control pinging is just letting me rip this cheap work of shed built greatness. Tbh I never checked crank or rod clearances because I didn’t have plastic age and normally use a micrometer anyway but it runs awesome so yay! But yea the 318 I’ve got which is super fun in the dodge aspen RT I have cost next to nothing and I encourage literally anyone who wants to start getting into muscle cars to go for a 318 build. So easy and the block itself or entire running engine for a couple hundred dollars tops! I’m an A body guy with f body pockets but what I have realized is that the 318 can do everything a 340 can do minus idk like 5%. Really good deal since they go running for 100 dollars or less.