Originally Posted by team423
I like the 275DEH it's listed as .515 of lift... I just don't want to do any work to the heads and stuff.. Iam also looking at the 268H it's listed at .494....just looked at the XE 262H it might be the one with .513,,should have no clearance issues I think.
The 275DEH is way too much camshaft for an otherwise bone stock 1977 460. Further, the exhaust lobe will provide 0.541" lift at the valve which risks retainer-to-guide interference and could damage the valve train. Since you said that you don't want to execute any valve train mods, your camshaft choices are somewhat limited beyond a stock camshaft. The XE262H is a lot of cam for an otherwise OEM engine as well; low end power will suffer. The 268H is an archaic grind and, frankly, not great for the engine and its appplication.
If you are going to blowl blend the intake bowls, the exhaust bowls, and port the exhaust ports, and also replace the pistons with 1988-1992 shallow dish pistons (~9.5:1 compression rartio with D3VE heads), then go with the 265DEH. If you are keeping the cavernous-dished OEM 1977 pistons then go with the 255DEH. Whichever of those two camshafts you select, note that they are supposed to be installed on a 106* intake centerline and therefore the camshaft should be properly phased during installation--simply using a 3-keyway double roller chain ain't gonna cut it since many of the double roller chains are broached to the 1972-up late OEM crankshaft gear specs anyway and so if the valve timing events are late the engine power will be lower than expected.