My new engine has developed a skip at idle. Reminds one of a vacuum leak. I replaced all vacuum lines, re torqued carburetor bolts, pulled all plugs and inspected them. All plugs looked great except for #8 cylinder which had a grayish tint. I flushed the new radiator and engine out to inspect cooling water. When I cranked it up i noticed steam and water coming out of tailpipe on passenger side. I drove it around to see if the water would dry out in tailpipe and it seemed to have a slight spark knock on acceleration . It did dry the majority of the water out but it still had a small amount of steam coming out of tailpipe. Could this problem have anything to do with the manifold gasket leaking or what does it sound like to you guys? What should I check next? Thanks

goes em toos de auto zones & rents de kits fors de radiators puressures & de combustions gasses in de coolants & sprays de carbs wirth em solvents to checkem vackcoms leakages

em toos dees thunks

That sounds like good advice to me.

I would suspect a head gasket. Have you looked at the engine oil yet?