95 F350 oil problem

[Ogre1]

One of our older fleet trucks with the 460 had a rebuild some time ago using an autozone shortblock. Problem is, since the rebuild (all I was involved in was dropping the motor back in the truck) it has had an issue with an oil leak. As near as I can tell, it appears to be putting a significant amount of oil out through the drivers side exhaust manifold. It obviously needs a new exhaust mani gasket, but it seems to me that there shouldn't be this much oil coming out through the exhaust. At one point, driving under a heavy load, enough oil pooled on top of the exhaust to start a fire on a plug wire. Any thoughts? Or should I just replace that gasket and keep on chuggin?