HO cam profile and flat lifters?

[LX5liter]

I'm not quite sure i'm clear on what your asking but I think you want to know if you can use an H.O. cam or if a flat tappet cam and lifters would work. If you use an H.O. cam then you should use the roller lifters, although its not a wild cam I think the ramp rates are too steep for a flat tappet. I'm sure you could use a flat tappet cam with matching lifters if you so desire as well. As far as firing order, use whichever firing order the cam is made for.

I hope this answers your question. If I missed what you were asking, i'm sorry .