camshaft and compression ratio
This for me is a new area too. I've decided to replace the previously installed enemic and sick 170 in my '65 with a 225. So I've been looking around. I do a decent amount of V8 work and the idea of getting more air and fuel in is pretty universal. But, a V8 has an intake event every 90° of crank rotation, the 6cyl only has an intake event every 120°. So it's easy to "overcam" them. So I'd keep things conservative, especially if you have power brakes and high (numerically low) rear gearing. If you are not going to add compression which I do think is extremely important, I wouldnt add a cam that's too much larger than 217°@ .050. Unfortunately, the cam choices as compared to a V8 are fairly dismal...lol. I'm not anywhere near the "building" phase but I think I'm going to get a custom cam for mine.