I am rebuilding a 454 to put in my K5, but I have a few questions first. How much lift can I run on 781 casting large open chamber oval port heads? The cam I want to run is a comp xtreme 4x4 hydr. with 270 int. and 278 exh. .544 and .564 lift, will this be a good cam for street and occasional towing? Also, anyone know the compression ratio, the casting number is XXX959, its a '78 truck engine? TIA :D

Got a 1980 454 with a wolverine cam that specs out at .498 lift, pulls like a freight train and drinks gas like one too!, with 4.56 gears it tachs about 3000 at 60 mph(235 85 16 tires).hope this helps ya.

the cam will work with stock valve springs, but you are on the edge. i might be a good idea to put a better set of springs on it. it is also on the top edge of being too big for 4x. i would get just a bit back as in a 260 duration with the lift in the .520 range. the stock compression is in the 7.8 to 8 to 1 range. mike

Thanks mike and horse. I decided to go with a little less cam. I am going to have the heads three angled and put new springs in, so it shouldn't be a problem, i was just didn't want to have to put new valves in.