Does anybody use the 285H cam from Schneider in a 455? The specs are I224-E230 duration at 50 and 512 lift on both I and E with 1.55 rockers. The lobe seperation is 112. Not sure what the overlap is. What do you think about it?
Thanks for the info. fellas. Scott, how does that fomula work to figure out overlap? I am paying attention to the overlap thing because I think thats one big contributor to low vacuum problems. I know someone who put the TA 290-08H cam in his 455, and now hes having power brake problems due to poor vacuum. That cam has 19 degrees of overlap at 50 thou, which is a good bit I think. It does pull like crazy when you get up in the RPM's though. I will give up some HP to have a more street friendly car though, which is why I was looking at the 285H.
19 deg OL at .050 is about the limit for cars with vacuum stuff (according to Jim W). The formula for OL at .050 is simply the average of the Int and Exh dur's at .050, minus twice the Lobe sep angle. You can verify for yourself by plotting the cam profile (lift vs crank angle) on graph paper (not the exact profile shape cuz you only know 3 or 4 data points but thats enough). Make sure everything is in crank degrees and not cam degrees. OL is then simply where the int and exh curves "overlap" (int opening and exh closing) on paper. Oh, and that formula only applies to a symmetrical profile. If you have the exact valve events (cam card), you can get the OL from that.
