There has been a bunch of good advice merely mentioned in the previous threads. Brief mentions often get glossed over. First, I want to repeat the great advice already given merely to reinforce the importance.
MOPAROFFICIAL suggested using Magnum heads. Box stock they will out-flow a really well-ported 302 casting. They have the smaller swirl combustion chamber (probably a better design than the 302), and the ports have much better geometry to maintain velocity without hurting flow. In addition to the intake manifold consideration, using Magnum heads on your '69 block will require AMC style lifters and hollow push rods. Virtually every small block Mopar aftermarket cam manufacturer uses AMC style lifters, so that one is easy. Mopar Performance at least used to sell the hollow push rods that would allow flat tappet cams in an older LA block with Magnum heads.
If you really want to stick with the 302s and do your own port work, watch as many YouTube videos as you can to pay attention to the seat and guide areas. I learned the 95-75-55 Rule that states most cylinder heads in stock form are capable of flowing 95% of maximum potential where the manifold bolts on. Gasket matching merely improves the strongest link in the chain. The area around the guide is capable of flowing 75% of maximum potential. Attention here will yield more returns than the same time spent gasket matching. The weak link in the chain will be the seat area -- the 55% zone. Ironically, it is the easiest part of the port to totally screw up. There are usually factory under cuts, poor blending with the rest of the port on one end, and the physical seat on the other. This is where you probably couldn't spend too much time on YouTube learning from those in the know.
I happen to be a big fan of the 302 casting 318 heads, but I'm a fuel economy guy, not a racer (MPGmike). I think they're a but anemic for the cam you chose. I would suggest nothing more radical than the factory '68 340 4-speed cam (which for that year only was a tad more aggressive than the automatic cam -- which became the 340 cam for '69+), or a 268 range Comp Cams or other alternative.
I wish you luck and ask you keep us posted as you move forward.
MOPAROFFICIAL suggested using Magnum heads. Box stock they will out-flow a really well-ported 302 casting. They have the smaller swirl combustion chamber (probably a better design than the 302), and the ports have much better geometry to maintain velocity without hurting flow. In addition to the intake manifold consideration, using Magnum heads on your '69 block will require AMC style lifters and hollow push rods. Virtually every small block Mopar aftermarket cam manufacturer uses AMC style lifters, so that one is easy. Mopar Performance at least used to sell the hollow push rods that would allow flat tappet cams in an older LA block with Magnum heads.
If you really want to stick with the 302s and do your own port work, watch as many YouTube videos as you can to pay attention to the seat and guide areas. I learned the 95-75-55 Rule that states most cylinder heads in stock form are capable of flowing 95% of maximum potential where the manifold bolts on. Gasket matching merely improves the strongest link in the chain. The area around the guide is capable of flowing 75% of maximum potential. Attention here will yield more returns than the same time spent gasket matching. The weak link in the chain will be the seat area -- the 55% zone. Ironically, it is the easiest part of the port to totally screw up. There are usually factory under cuts, poor blending with the rest of the port on one end, and the physical seat on the other. This is where you probably couldn't spend too much time on YouTube learning from those in the know.
I happen to be a big fan of the 302 casting 318 heads, but I'm a fuel economy guy, not a racer (MPGmike). I think they're a but anemic for the cam you chose. I would suggest nothing more radical than the factory '68 340 4-speed cam (which for that year only was a tad more aggressive than the automatic cam -- which became the 340 cam for '69+), or a 268 range Comp Cams or other alternative.
I wish you luck and ask you keep us posted as you move forward.
