Ok I know that its really hard to tell from such little numbers, but I am hoping that people have just kind of heard story's in the past. I am looking at some speed inc rgr heads and the guy has a futral f13 cam that will work with it, but there is another guy that has a ms3 cam for sale and I know that ms3 has some bigger numbers. I just dont know if I will have to worry about my pistions hitting or if they are ment to be fine or if the f13 is just close enough to not worry about it at all. Well I hope you have some help for me. Thank you so much

 

The MS3 at 237/242 .603/.609 is too big for a stock motor IMO, unless you like having no bottom-end power. It's a mid-high rpm cam made for a 1/4 car with big gears and a big converter. You can expect to not make power until 4000+ rpm if you're using it on stock cubes.

Yes, you'll need to check PtV clearance on that cam with aftermarket heads.

The F-13 would be a much better cam for an NA 346ci street car application IMO.