I have a 5.0 HO roller that is All stock. I also have a 5.0 HO that someone had changed it over to a flat tappet hydrolic, it still has the factory roller rockers and corrected length push rods in it. It came out of a mud bogger and ran strong, the cooling system failed and so did the driver. I also have a set of GT-40-p heads that Im doing some port work to and a GT-40 intake with a 70mm BBK T-body.
I would like to put this cam and lifter set up in my stock block with the GT-40 heads, intake and 70mm but need some input before I do anything.

 

First this thread doesn't belong in Tech.....it belongs in the general discussion so I will move it for you

All you need to do to use a flat tappet cam in a roller motor is put the cam and the flat tappet lifters in with it.

Having said that you can NOT take a flat tappet motor and just slap in a roller cam and lifers an call it good. It takes a little modification for that to happen.

Just a FYI though....the stock cam is a great cam for what you need. Do you know the specs of the cam? Brand? Its RPM range?